普及 1 第 10 题 Runtime Error (RE) 求条：
#include <cstdio>
int main(void)
{
int n, m, q, a[3000][3000], sum[3000][3000];
scanf("%d %d %d", &n, &m, &q);
for (int i = 1; i <= n; i++)
{
for (int j = 1; j <= m; j++)
{
scanf("%d", &a[i][j]);
sum[i][j] = sum[i - 1][j] + sum[i][j - 1] - sum[i - 1][j - 1] + a[i][j];
}
}
for (int i = 0; i < q; i++)
{
int x1, y1, x2, y2;
scanf("%d %d %d %d", &x1, &y1, &x2, &y2);
printf("%d\n", sum[x2][y2] - sum[x1 - 1][y2] - sum[x2][y1 - 1] + sum[x1 - 1][y1 - 1]);
}
return 0;
}