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Find the Path – HackerRank Solution Java , Python 3, Python 2 , C , C++, Best and Optimal Solutions , All you need.
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C++ Find the Path HackerRank Solution
#include <bits/stdc++.h>
using namespace std;
int N, M;
vector<vector<int64_t>> G;
const int64_t INF = 1e11;
vector<vector<int64_t>> dijk(int r, int c, int L, int R) {
set<pair<int64_t, pair<int, int>>> Q;
vector<vector<int64_t>> D(N, vector<int64_t>(R-L+1, INF));
Q.insert(make_pair(0, make_pair(r,c)));
vector<vector<int>> dirs = {{1,0},{0,1},{-1,0},{0,-1}};
while (!Q.empty()) {
auto curr = *Q.begin();
Q.erase(Q.begin());
int64_t d = curr.first;
int r = curr.second.first, c = curr.second.second;
if (d > D[r][c-L]) {
continue;
}
// cout << r << " " << c << endl;
D[r][c-L] = d;
for (auto dir : dirs) {
int cr = r+dir[0];
int cc = c+dir[1];
if (cr < 0 || cc < L || cr >= N || cc > R)
continue;
int64_t cd = d + G[cr][cc];
if (cd < D[cr][cc-L]) {
Q.insert(make_pair(cd, make_pair(cr, cc)));
D[cr][cc-L] = cd;
}
}
}
return D;
}
vector<vector<int>> Qs;
vector<int64_t> ans;
vector<unordered_map<int, pair<int, vector<vector<int64_t>>>>> SPs(7);
void div_and_conq(int l, int r, vector<int> Qis) {
if (l > r)
return;
int mid = (r+l)/2;
// cout << l << " " << r << " " << mid << endl;
for (int i = 0; i < N; ++i) {
SPs[i][mid] = make_pair(l, dijk(i, mid, l, r));
// cout << i << endl;
// for (auto& v : SPs[i][mid].second) {
// for (int d : v) {
// cout << d << " ";
// }
// cout << endl;
// }
}
vector<int> Qls, Qrs;
for (int i : Qis) {
// cout << ": ";
// for (int q : Qs[i]) {
// cout << q << " ";
// }
if (Qs[i][1] < mid && Qs[i][3] < mid) {
Qls.push_back(i);
} else if (Qs[i][1] > mid && Qs[i][3] > mid) {
Qrs.push_back(i);
} else {
// cout << " *";
for (int j = 0; j < N; ++j) {
for (auto& kv : SPs[j]) {
int mid = kv.first;
int upperl = kv.second.first;
auto& SP = kv.second.second;
int64_t d = SP[Qs[i][0]][Qs[i][1]-upperl]+SP[Qs[i][2]][Qs[i][3]-upperl]+G[j][mid];
// if ((Qs[i][0] == j && Qs[i][1] == mid) || (Qs[i][2] == j && Qs[i][3] == mid))
// d -= G[j][mid];
ans[i] = min(ans[i], d);
}
}
}
// cout << endl;
}
div_and_conq(l, mid-1, Qls);
div_and_conq(mid+1, r, Qrs);
for (int i = 0; i < N; ++i) {
SPs[i].erase(mid);
}
}
int main() {
ios::sync_with_stdio(false);
cin >> N >> M;
G.assign(N, vector<int64_t>(M));
for (auto &v : G) {
for (int64_t& i : v) {
cin >> i;
}
}
int Q;
cin >> Q;
Qs.resize(Q);
ans.assign(Q, INF);
vector<int> Qis;
for (int i = 0; i < Q; ++i) {
int a,b,c,d;
cin >> a >> b >> c >> d;
Qs[i] = {a,b,c,d};
Qis.push_back(i);
}
div_and_conq(0, M-1, Qis);
for (int64_t i : ans) {
cout << i << endl;
}
return 0;
}
Java Find the Path HackerRank Solution
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.InputMismatchException;
public class C {
InputStream is;
PrintWriter out;
String INPUT = "";
void solve()
{
int n = ni(), m = ni();
int[][] a = new int[m][n];
for(int i = 0;i < n;i++){
for(int j = 0;j < m;j++){
a[j][i] = ni();
}
}
d = new long[m][n][][];
build(0, m, a);
int Q = ni();
for(int q = 0;q < Q;q++){
int sc = ni(), sr = ni();
int tc = ni(), tr = ni();
if(sr > tr){
{int du = tr; tr = sr; sr = du;}
{int du = tc; tc = sc; sc = du;}
}
out.println(go(0, m, sr, sc, tr, tc, a));
}
}
static long go(int L, int R, int sr, int sc, int tr, int tc, int[][] a)
{
int M = L+R>>>1;
int m = a[0].length;
long ret = Long.MAX_VALUE;
for(int i = 0;i < m;i++){
ret = Math.min(ret, d[M][i][sr-L][sc] + d[M][i][tr-L][tc] - a[M][i]);
}
if(sr <= M && M <= tr){
return ret;
}
if(R-L <= 1)return ret;
if(tr < M){
return Math.min(ret, go(L, M, sr, sc, tr, tc, a));
}else{
return Math.min(ret, go(M, R, sr, sc, tr, tc, a));
}
}
static long[][][][] d;
static void build(int L, int R, int[][] a)
{
int m = a[0].length;
int M = L+R>>>1;
if(d[M][0] != null)return;
for(int i = 0;i < m;i++){
d[M][i] = dijk(a, M, i, L, R);
}
if(R-L <= 1)return;
build(L, M, a);
build(M, R, a);
}
public static long[][] dijk(int[][] a, int sr, int sc, int L, int R)
{
int m = a[0].length;
long[][] td = new long[R-L][m];
for(int i = 0;i < R-L;i++){
Arrays.fill(td[i], Long.MAX_VALUE / 3);
}
td[sr-L][sc] = 0;
MinHeapL q = new MinHeapL((R-L)*m);
q.add((sr-L)*m+sc, 0L);
td[sr-L][sc] = a[sr][sc];
int[] dr = { 1, 0, -1, 0 };
int[] dc = { 0, 1, 0, -1 };
while(q.size() > 0){
int cur = q.argmin();
q.remove(cur);
int r = cur / m, c = cur % m;
for(int k = 0;k < 4;k++){
int nr = r + dr[k], nc = c + dc[k];
if(nr >= L-L && nr < R-L && nc >= 0 && nc < m){
long nd = td[r][c] + a[nr+L][nc];
if(nd < td[nr][nc]){
td[nr][nc] = nd;
q.update(nr*m+nc, nd);
}
}
}
}
return td;
}
public static class MinHeapL {
public long[] a;
public int[] map;
public int[] imap;
public int n;
public int pos;
public static long INF = Long.MAX_VALUE;
public MinHeapL(int m)
{
n = Integer.highestOneBit((m+1)<<1);
a = new long[n];
map = new int[n];
imap = new int[n];
Arrays.fill(a, INF);
Arrays.fill(map, -1);
Arrays.fill(imap, -1);
pos = 1;
}
public long add(int ind, long x)
{
int ret = imap[ind];
if(imap[ind] < 0){
a[pos] = x; map[pos] = ind; imap[ind] = pos;
pos++;
up(pos-1);
}
return ret != -1 ? a[ret] : x;
}
public long update(int ind, long x)
{
int ret = imap[ind];
if(imap[ind] < 0){
a[pos] = x; map[pos] = ind; imap[ind] = pos;
pos++;
up(pos-1);
}else{
a[ret] = x;
up(ret);
down(ret);
}
return x;
}
public long remove(int ind)
{
if(pos == 1)return INF;
if(imap[ind] == -1)return INF;
pos--;
int rem = imap[ind];
long ret = a[rem];
map[rem] = map[pos];
imap[map[pos]] = rem;
imap[ind] = -1;
a[rem] = a[pos];
a[pos] = INF;
map[pos] = -1;
up(rem);
down(rem);
return ret;
}
public long min() { return a[1]; }
public int argmin() { return map[1]; }
public int size() { return pos-1; }
private void up(int cur)
{
for(int c = cur, p = c>>>1;p >= 1 && a[p] > a[c];c>>>=1, p>>>=1){
long d = a[p]; a[p] = a[c]; a[c] = d;
int e = imap[map[p]]; imap[map[p]] = imap[map[c]]; imap[map[c]] = e;
e = map[p]; map[p] = map[c]; map[c] = e;
}
}
private void down(int cur)
{
for(int c = cur;2*c < pos;){
int b = a[2*c] < a[2*c+1] ? 2*c : 2*c+1;
if(a[b] < a[c]){
long d = a[c]; a[c] = a[b]; a[b] = d;
int e = imap[map[c]]; imap[map[c]] = imap[map[b]]; imap[map[b]] = e;
e = map[c]; map[c] = map[b]; map[b] = e;
c = b;
}else{
break;
}
}
}
}
void run() throws Exception
{
is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes());
out = new PrintWriter(System.out);
long s = System.currentTimeMillis();
solve();
out.flush();
if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms");
}
public static void main(String[] args) throws Exception { new C().run(); }
private byte[] inbuf = new byte[1024];
private int lenbuf = 0, ptrbuf = 0;
private int readByte()
{
if(lenbuf == -1)throw new InputMismatchException();
if(ptrbuf >= lenbuf){
ptrbuf = 0;
try { lenbuf = is.read(inbuf); } catch (IOException e) { throw new InputMismatchException(); }
if(lenbuf <= 0)return -1;
}
return inbuf[ptrbuf++];
}
private boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); }
private int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; }
private double nd() { return Double.parseDouble(ns()); }
private char nc() { return (char)skip(); }
private String ns()
{
int b = skip();
StringBuilder sb = new StringBuilder();
while(!(isSpaceChar(b))){ // when nextLine, (isSpaceChar(b) && b != ' ')
sb.appendCodePoint(b);
b = readByte();
}
return sb.toString();
}
private char[] ns(int n)
{
char[] buf = new char[n];
int b = skip(), p = 0;
while(p < n && !(isSpaceChar(b))){
buf[p++] = (char)b;
b = readByte();
}
return n == p ? buf : Arrays.copyOf(buf, p);
}
private char[][] nm(int n, int m)
{
char[][] map = new char[n][];
for(int i = 0;i < n;i++)map[i] = ns(m);
return map;
}
private int[] na(int n)
{
int[] a = new int[n];
for(int i = 0;i < n;i++)a[i] = ni();
return a;
}
private int ni()
{
int num = 0, b;
boolean minus = false;
while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
if(b == '-'){
minus = true;
b = readByte();
}
while(true){
if(b >= '0' && b <= '9'){
num = num * 10 + (b - '0');
}else{
return minus ? -num : num;
}
b = readByte();
}
}
private long nl()
{
long num = 0;
int b;
boolean minus = false;
while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
if(b == '-'){
minus = true;
b = readByte();
}
while(true){
if(b >= '0' && b <= '9'){
num = num * 10 + (b - '0');
}else{
return minus ? -num : num;
}
b = readByte();
}
}
private static void tr(Object... o) { System.out.println(Arrays.deepToString(o)); }
}
Python 3 Find the Path HackerRank Solution
#!/bin/python3
import sys
from collections import deque
from math import inf
from heapq import heappush, heappop
def shortestPath (matrix, query, numRows, numCols): # Breadth First Search
start = (query[0],query[1])
goal = (query[2],query[3])
pathWeight = matrix[start]
pathQueue = []
heappush(pathQueue, [pathWeight, start[0], start[1]])
seen = {start:pathWeight}
minWeight = inf
while pathQueue:
pathCell = heappop(pathQueue)
row, col = (pathCell[1], pathCell[2])
pathWeight = pathCell[0]
if (row, col) == goal:
if pathWeight < minWeight:
minWeight = pathWeight
continue
if pathWeight >= minWeight:
continue
for newRow, newCol in ((row+1,col), (row-1,col), (row,col+1), (row,col-1)):
if 0 <= newRow < numRows and 0 <= newCol < numCols:
newPathWeight = pathWeight + matrix [(newRow,newCol)]
if (newRow,newCol) in seen:
if seen[(newRow, newCol)] <= newPathWeight:
continue
heappush(pathQueue, [newPathWeight, newRow, newCol])
seen[(newRow, newCol)] = newPathWeight
return minWeight
if __name__ == "__main__":
m, n = input().strip().split(' ')
m, n = [int(m), int(n)]
matrix = {}
for matrixRow in range(m):
matrixRowList = [int(weight) for weight in input().strip().split(' ')]
for matrixCol in range(n):
matrix[(matrixRow,matrixCol)] = matrixRowList[matrixCol]
q = int(input().strip())
for queries in range(q):
query = [int(query_temp) for query_temp in input().strip().split(' ')]
print(shortestPath(matrix, query, m, n))
Python 2 Find the Path HackerRank Solution
# Enter your code here. Read input from STDIN. Print output to STDOUT
import sys
from heapq import *
Row_Count = 0
Col_Count = 0
Query_Count = 0
Table = []
Query_Dict = {}
Query_Results = []
Shortest_Paths = []
Visited = []
def readInput():
global Row_Count, Col_Count, Query_Count, Table, Query_Dict, Query_Results, Shortest_Paths, Visited
Row_Count, Col_Count = map(int, raw_input().split())
for i in xrange(Row_Count):
row = []
entry_list = raw_input().split()
for j in xrange(Col_Count):
row.append(int(entry_list[j]))
Table.append(row)
Shortest_Paths = [ [ sys.maxint for j in range(Col_Count) ] for i in range(Row_Count) ]
Visited = [ [ False for j in range(Col_Count) ] for i in range(Row_Count) ]
Query_Count = int(raw_input())
for i in xrange(Query_Count):
Query_Results.append(sys.maxint)
query = map(int, raw_input().split())
if query[1] > query[3]:
query = (query[2], query[3], query[0], query[1])
else:
query = (query[0], query[1], query[2], query[3])
if not Query_Dict.has_key(query):
Query_Dict[query] = []
Query_Dict[query].append(i)
def isValidSquare(row, col, left_bound, right_bound):
return row >= 0 and row < Row_Count and col >= left_bound and col <= right_bound
def processSingleSquare(start_row, start_col, left_bound, right_bound):
global Shortest_Paths, Visited
for i in range(Row_Count):
for j in range(left_bound, right_bound + 1):
Shortest_Paths[i][j] = sys.maxint
Visited[i][j] = False
bfs_heap = []
Shortest_Paths[start_row][start_col] = Table[start_row][start_col]
heappush(bfs_heap, (Table[start_row][start_col], start_row, start_col))
while bfs_heap:
weight, row, col = heappop(bfs_heap)
if Visited[row][col]:
continue
Visited[row][col] = True
if isValidSquare(row - 1, col, left_bound, right_bound) and not Visited[row - 1][col] :
if weight + Table[row - 1][col] < Shortest_Paths[row - 1][col]:
Shortest_Paths[row - 1][col] = weight + Table[row - 1][col]
heappush(bfs_heap, (weight + Table[row - 1][col], row - 1, col))
if isValidSquare(row + 1, col, left_bound, right_bound) and not Visited[row + 1][col]:
if weight + Table[row + 1][col] < Shortest_Paths[row + 1][col]:
Shortest_Paths[row + 1][col] = weight + Table[row + 1][col]
heappush(bfs_heap, (weight + Table[row + 1][col], row + 1, col))
if isValidSquare(row, col - 1, left_bound, right_bound) and not Visited[row][col - 1]:
if weight + Table[row][col - 1] < Shortest_Paths[row][col - 1]:
Shortest_Paths[row][col - 1] = weight + Table[row][col - 1]
heappush(bfs_heap, (weight + Table[row][col - 1], row, col - 1))
if isValidSquare(row, col + 1, left_bound, right_bound) and not Visited[row][col + 1]:
if weight + Table[row][col + 1] < Shortest_Paths[row][col + 1]:
Shortest_Paths[row][col + 1] = weight + Table[row][col + 1]
heappush(bfs_heap, (weight + Table[row][col + 1], row, col + 1))
def processOnlyOneColumn(start_row, col_index):
shortest_paths = [ sys.maxint for i in range(Row_Count) ]
shortest_paths[start_row] = Table[start_row][col_index]
weight = Table[start_row][col_index]
for i in reversed(range(0, start_row)):
weight = weight + Table[i][col_index]
shortest_paths[i] = weight
weight = Table[start_row][col_index]
for i in range(start_row + 1, Row_Count):
weight = weight + Table[i][col_index]
shortest_paths[i] = weight
return shortest_paths
def processQueriesByColumn(left_col, right_col, whole_queries):
global Query_Results
if not whole_queries:
return
if left_col >= right_col:
for query in whole_queries:
query_indexes = whole_queries[query]
paths = processOnlyOneColumn(query[0], left_col)
new_min = min(Query_Results[query_indexes[0]], paths[query[2]])
for q_index in query_indexes:
Query_Results[q_index] = new_min
return
paths = []
middle_col = (left_col + right_col) / 2
for i in xrange(Row_Count):
processSingleSquare(i, middle_col, left_col, right_col)
for query in whole_queries:
query_indexes = whole_queries[query]
tmp_w = Shortest_Paths[query[0]][query[1]] + Shortest_Paths[query[2]][query[3]] - Table[i][middle_col]
if tmp_w < Query_Results[query_indexes[0]]:
for q_index in query_indexes:
Query_Results[q_index] = tmp_w
queries_on_left = {}
queries_on_right = {}
for query in whole_queries:
query_indexes = whole_queries[query]
if query[3] < middle_col:
queries_on_left[query] = query_indexes
if query[1] > middle_col:
queries_on_right[query] = query_indexes
processQueriesByColumn(left_col, middle_col - 1, queries_on_left)
processQueriesByColumn(middle_col + 1, right_col, queries_on_right)
def printQueryResults():
for q_result in Query_Results:
print q_result
if __name__ == '__main__':
readInput()
processQueriesByColumn(0, Col_Count - 1, Query_Dict)
printQueryResults()
C Find the Path HackerRank Solution
#include <assert.h>
#include <limits.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MIN(a,b) (((a)<(b))?(a):(b))
#define MAX(a,b) (((a)>(b))?(a):(b))
#define MAX_N 7
#define MAX_M 5000
#define LOG2_MAX_M 13
#define MAX_Q 30000
#define INFINITY INT_MAX
#define N(r, c) ((r) * (m) + (c))
#define ROW(n) ((n) / (m))
#define COL(n) ((n) % (m))
#define HEAP_KEY(pri, n) (((uint64_t)pri << 32) | n)
#define HEAP_PRI(key) ((int)(key >> 32))
#define HEAP_N(key) ((int)key)
#define PARENT(i) (((i) - 1) / 2)
#define LEFT(i) (2 * (i) + 1)
#define RIGHT(i) (2 * (i) + 2)
typedef uint64_t heap_type;
struct node {
int depth;
int left, mid, right;
struct node *child[2];
};
struct node *root;
static int n;
static int m;
static int q;
static int visited[MAX_N * MAX_M];
static int length[MAX_N * MAX_M];
static int dist[LOG2_MAX_M][MAX_N][MAX_N * MAX_M];
static heap_type queue[MAX_N * MAX_M * 4];
static int num_queue;
static inline void swap_node(heap_type *a, int x, int y) {
heap_type tmp = a[x];
a[x] = a[y];
a[y] = tmp;
}
static void sift_down(heap_type *a, int i, int size) {
while (1) {
int l = LEFT(i);
int r = RIGHT(i);
int min;
if (r >= size) {
if (l >= size) {
break;
}
min = l;
} else {
if (a[r] >= a[l]) {
min = l;
} else {
min = r;
}
}
if (a[min] >= a[i]) {
break;
}
swap_node(a, i, min);
i = min;
}
}
static void sift_up(heap_type *a, int i, int size) {
while (i) {
int p = PARENT(i);
// sift up until parent is less than node
if (a[p] <= a[i]) {
break;
}
swap_node(a, p, i);
i = p;
}
}
static void pop_heap(heap_type *a, int size) {
swap_node(a, 0, size-1);
sift_down(a, 0, size-1);
}
static void push_heap(heap_type *a, int size) {
sift_up(a, size-1, size);
}
static void dijkstra(struct node *s, int i, int begin) {
int *mind = dist[s->depth][i];
// reset state
for (int r = 0; r < n; r++) {
for (int c = s->left; c <= s->right; c++) {
visited[N(r,c)] = 0;
mind[N(r,c)] = INFINITY;
}
}
num_queue = 0;
// seed queue
mind[begin] = length[begin];
queue[num_queue++] = HEAP_KEY(mind[begin], begin);
push_heap(queue, num_queue);
while (num_queue) {
// pop node with shortest path
pop_heap(queue, num_queue);
int u = queue[--num_queue];
visited[u] = 1;
// visit adjacent children
static const int offsets[] = {
0, -1, 0, 1,
-1, 0, 1, 0
};
for (int j = 0; j < 4; j++) {
int vr = ROW(u) + offsets[j];
int vc = COL(u) + offsets[4+j];
// ignore out of bounds children
if (vr < 0 || vr >= n || vc < s->left || vc > s->right) {
continue;
}
// ignore children which have already been visited
int v = N(vr, vc);
if (visited[v]) {
continue;
}
int alt = mind[u] + length[v];
if (alt < mind[v]) {
mind[v] = alt;
// push new element to queue
assert(num_queue < MAX_N * MAX_M * 4);
queue[num_queue++] = HEAP_KEY(alt, v);
push_heap(queue, num_queue);
}
}
}
}
void free_node(struct node *root) {
if (!root) {
return;
}
free_node(root->child[0]);
free_node(root->child[1]);
free(root);
}
struct node *alloc_node(int depth, int left, int right) {
struct node *s = calloc(sizeof(struct node), 1);
s->depth = depth;
s->left = left;
s->right = right;
s->mid = s->left + (s->right - s->left) / 2;
// compute dijkstra for all all rows along the middle line
for (int i = 0; i < n; i++) {
dijkstra(s, i, N(i, s->mid));
}
return s;
}
int mind_r(struct node *s, int r1, int c1, int r2, int c2) {
int min = INT_MAX;
for (int i = 0; i < n; i++) {
int *mind = dist[s->depth][i];
int d = mind[N(r1, c1)] + mind[N(r2, c2)] - length[N(i, s->mid)];
min = MIN(min, d);
}
// if the query crossed the middle, this is absolutely the shortest path
if (c1 <= s->mid && c2 >= s->mid) {
return min;
}
// else, there may be a shorter path in one of the children
else if (c2 < s->mid) {
if (!s->child[0]) {
s->child[0] = alloc_node(s->depth+1, s->left, s->mid-1);
}
int lmin = mind_r(s->child[0], r1, c1, r2, c2);
return MIN(min, lmin);
} else {
if (!s->child[1]) {
s->child[1] = alloc_node(s->depth+1, s->mid+1, s->right);
}
int rmin = mind_r(s->child[1], r1, c1, r2, c2);
return MIN(min, rmin);
}
}
int mind(int r1, int c1, int r2, int c2) {
if (!root) {
root = alloc_node(0, 0, m-1);
}
return mind_r(root, r1, c1, r2, c2);
}
int main() {
scanf("%d %d", &n, &m);
for (int i = 0; i < n * m; i++) {
scanf("%d", &length[i]);
}
int q;
scanf("%d", &q);
for (int i = 0; i < q; i++) {
int r1, c1, r2, c2;
scanf("%d %d %d %d", &r1, &c1, &r2, &c2);
// keep begin to the left of end
if (c1 > c2) {
int tmp = r1;
r1 = r2;
r2 = tmp;
tmp = c1;
c1 = c2;
c2 = tmp;
}
printf("%d\n", mind(r1, c1, r2, c2));
}
// cleanup
free_node(root);
return 0;
}
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