lanqiao 2109 统计子矩阵(一维前缀和+滑动窗口)

13lanqiao/test6-2.cpp

@@ -0,0 +1,38 @@
+// lanqiao 2109 统计子矩阵(一维前缀和+滑动窗口)
+#include<bits/stdc++.h>
+using namespace std;
+#define int long long
+const int N = 5e2 + 10;
+int n, m, k;
+int a[N][N], sum[N][N];
+signed main(){
+    cin >> n >> m >> k;
+    for(int i = 1; i <= n; i ++){
+        for(int j = 1; j <= m; j++){
+            cin >> a[i][j];
+            sum[i][j] = sum[i-1][j] + a[i][j];
+        }
+    }
+    int ans = 0;
+    for(int i = 1; i <= n; i++){
+        for(int i1 = i; i1 <= n; i1++){
+            int l = 1, r, s = 0;
+            for(r = 1; r <= m; r++){
+                s += sum[i1][r] - sum[i-1][r];
+                while(s > k){
+                    s -= sum[i1][l] - sum[i-1][l];
+                    l++;
+                }
+                ans += r - l + 1;
+            }   
+        }
+    }
+    cout << ans << endl;
+    return 0;
+}
+/* samples -> 19
+3 4 10
+1 2 3 4
+5 6 7 8
+9 10 11 12
+*/