Added 994. Rotting Oranges

Create Cpp Solutio.cpp

Author: HimeshKohad

Solutions/994. Rotting Oranges/Cpp Solutio.cpp

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+class Solution {
+public:
+ int orangesRotting(vector<vector<int>>& grid) {
+ int n = grid.size();
+ int m = grid[0].size();
+
+ // format: {{row, col}, time}
+ queue<pair<pair<int, int>, int>> q;
+ // visited array: copy of original grid
+ vector<vector<int>> vis(n, vector<int>(m));
+
+ for (int i = 0; i < n; ++i) {
+ for (int j = 0; j < m; ++j) {
+ if (grid[i][j] == 2) {
+ q.push({{i, j}, 0});
+ vis[i][j] = 2; // Use 2 to indicate a rotten orange
+ }
+ else {
+ vis[i][j] = grid[i][j]; // Use the grid values directly
+ }
+ }
+ }
+
+ int time = 0;
+ // 4-directional neighbours
+ int dRow[] = {0, 1, 0, -1};
+ int dCol[] = {1, 0, -1, 0};
+
+ while (!q.empty()) {
+ int r = q.front().first.first;
+ int c = q.front().first.second;
+ int t = q.front().second;
+ time = max(time, t);
+ q.pop();
+
+ for (int i = 0; i < 4; ++i) {
+ int nrow = r + dRow[i];
+ int ncol = c + dCol[i];
+
+ if (nrow >= 0 && nrow < n && ncol >= 0 && ncol < m && vis[nrow][ncol] == 1
+ && grid[nrow][ncol] == 1) {
+ q.push({{nrow, ncol}, t + 1});
+ vis[nrow][ncol] = 2; // Use 2 to indicate a rotten orange
+ }
+ }
+ }
+
+ // Check and return -1, if fresh oranges are left
+ for (int i = 0; i < n; ++i) {
+ for (int j = 0; j < m; ++j) {
+ if (vis[i][j] == 1) {
+ return -1;
+ }
+ }
+ }
+
+ return time;
+ }
+};