二维前缀和模板题:P2004 领地选择
思路:就是使用二维前缀和的模板:
先放模板:
#include<iostream> using namespace std; #define ll long long const int maxn = 1e3 + 10; ll a[maxn][maxn], jx[maxn][maxn]; ll n, m, L, xa, ya, xb, yb; ll aa, bb, maxx = 0; int main(){ cin >> n >> m>>L; for (int i = 1; i <= n;++i) for (int j = 1; j <= m; ++j) cin >> a[i][j]; for (int i = 1; i <= n;++i) for (int j = 1; j <= m; ++j) jx[i][j] = a[i][j] + jx[i - 1][j] + jx[i][j - 1] - jx[i - 1][j - 1]; for (int i = 1; i <= n - L+1;++i) for (int j = 1; j <= m - L+1; ++j) { xa = i; ya = j; xb = i + L-1; yb = j + L-1; ll sum = jx[xb][yb] - jx[xa-1][yb] - jx[xb][ya-1] + jx[xa-1][ya-1]; if (maxx < sum){ maxx = sum; aa = xa; bb = ya; } } cout << aa << " " << bb << endl; }