前缀和与差分

前缀和与差分 1.AcWing795.一维前缀和1234567891011121314int n, m;int arr[MAX], prefix[MAX];int main() { scanf("%d %d", &n, &m); for (int i = 1; i <= n; ++i) scanf("%d", &arr[i]); for (int i = 1; i <= n; ++i) prefix[i] = prefix[i - 1] + arr[i];//前缀和数组初始化 while (m--) { int low, high; scanf("%d %d", &low, &high); printf("%d\n", prefix[high] - prefix[low - 1]); } return 0;} 2.AcWing796.二维前缀和1234567891011121314151617int n, m, q;int arr[MAX][MAX], prefix[MAX][MAX];nt main() { scanf("%d %d %d", &n, &m, &q); for (int i = 1; i <= n; ++i) for (int j = 1; j <= m; ++j) scanf("%d", &arr[i][j]); for (int i = 1; i <= n; ++i) for (int j = 1; j <= m; ++j) prefix[i][j] = prefix[i - 1][j] + prefix[i][j - 1] - prefix[i - 1][j - 1] + arr[i][j];//前缀初始化 while (q--) { int x1, y1, x2, y2; ...