CF427 C star sky 二维数组前缀和

Posted 2020-09-30

用pre[t][i][j]存时间等价于t时坐标(1, 1) 和(i, j)组成的矩形区域的星星总亮度。再注意一下一个坐标处可以有多颗星星就可以了。

 star sky

 1 // http://codeforces.com/contest/835/problem/C
 2 #include <cstdio> 
 3 #include <cstring>
 4 const int M = 12, N = 102;
 5 int pre[M][N][N];
 6 int main()
 7 {
 8     int n, q, c;
 9     while(~scanf("%d%d%d", &n, &q, &c)) {
10         memset(pre, 0, sizeof pre);
11         c++;
12         int x, y, s;
13         while(n--) {
14             scanf("%d%d%d", &x, &y, &s);
15             for (int i = 0; i < c; ++i)
16                 pre[i][x][y] += (s + i) % c; //不易注意的地方，同一个坐标可能有多颗小星星 
17         }
18         for (int t = 0; t < c; ++t) //时间t，求下二维前缀和 
19             for (int i = 1; i <= 100; ++i)
20                 for (int j = 1; j <= 100; ++j)
21                     pre[t][i][j] += pre[t][i-1][j] + pre[t][i][j-1] - pre[t][i-1][j-1];
22         int t, x1, y1, x2, y2;
23         while(q--) {
24             scanf("%d%d%d%d%d", &t, &x1, &y1, &x2, &y2);
25             t %= c;
26             int sum = pre[t][x2][y2] - pre[t][x1-1][y2] - pre[t][x2][y1-1] + pre[t][x1-1][y1-1];
27             printf("%d\n", sum); 
28         }
29     }
30     
31     return 0;
32 }