Photoshoot

    1#include <bits/stdc++.h>
    2using namespace std;
    3int main() {
    4    ios::sync_with_stdio(0); cin.tie(0); 
    5    int n, k, q; cin >> n >> k >> q;
    6    ///we maintain previous window and updated window. suprisingly easier than p1
    7    //throwing 2d seg tree at this problem is too hard so we just brute force!!!!
    8    //since k is so tiny we brute force. We do not need to loop all k * k squares only the ones influenced
    9    //the cur[i][j] will be the sum of beauty values inside the k × k square and top left corner is row i col j
    10    vector<vector<int>> pre(n, vector<int>(n)), cur(n, vector<int>(n));
    11    int ans = 0;
    12    while (q--) {
    13        int r, c, v; cin >> r >> c >> v;
    14        r--; c--;
    15        int change = v - pre[r][c];
    16        pre[r][c] = v;
    17        // boundaries of winodws
    18        int topr = max(0, r - k + 1), bottomr = min(r, n - k), leftcol = max(0, c - k + 1), rightcol = min(c, n - k);
    19        //all windows affected by this update 
    20        for (int i = topr; i <= bottomr; i++) {
    21            for (int j = leftcol; j <= rightcol; j++) {
    22                cur[i][j] += change;
    23                ans = max(ans, cur[i][j]);
    24            }
    25        }
    26        cout << ans << '\n';
    27    }
    28    return 0;
    29}