int cursor = 0;
for (int i = 0; ; ++i) {
for (int j = 0; j <= i; ++j) {
M[j][i - j] = A[cursor];
cursor = (cursor + 1) % L;
}
}
题目意思
给你一个T,表示案例数量,给次给一个n,n个数字,要求按上面公式打表,每次询问,给两个点,要求计算以两个点位顶点的矩阵中元素的和。
多打几次表,可以发现当n为奇数时,a[i][j]=a[i-2n][j]=a[i][j-2n]
,所以对每个点分块化,其中query函数是求(0,0)与(i,j)构成的矩阵中的元素和,具体看AC代码。
#include <iostream>
using namespace std;
int map[100][100], sum[100][100];
int n;
long long query(int x, int y)
{
if (x < 0 || y < 0)
return 0;
x++;
y++;
int t = 2 * n;
long long int ans = 0;
ans += (long long)sum[t - 1][t - 1] * (x/t)*(y/t);
if (x % t != 0)
ans += (long long)sum[x%t - 1][t - 1] * (y / t);
if (y % t != 0)
ans += (long long)sum[t - 1][y%t - 1] * (x / t);
if (x % t != 0 && y % t != 0)
ans += (long long)sum[x%t - 1][y%t - 1];
return ans;
}
int main()
{
int t, q, lx, ly, rx, ry;
scanf("%d", &t);
while (t--)
{
scanf("%d", &n);
int array[11];
for (int i = 0; i < n; i++)
scanf("%d", &array[i]);
int cursor = 0;
for (int i = 0; i < 4 * n; ++i)
{
for (int j = 0; j <= i; ++j)
{
map[j][i - j] = array[cursor];
cursor = (cursor + 1) % n;
}
}
/*
for (int i = 0; i < 4 * n; ++i)
{
for (int j = 0; j < 4 * n; ++j)
printf("%5d", map[i][j]);
printf("\n");
}
*/
sum[0][0] = map[0][0];
for (int i = 1; i <= 2 * n; i++)
sum[0][i] = sum[0][i - 1] + map[0][i];
for (int i = 1; i <= 2 * n; i++)
{
sum[i][0] = sum[i - 1][0] + map[i][0];
for (int j = 1; j <= 2 * n; j++)
sum[i][j] = sum[i - 1][j] + sum[i][j - 1] - sum[i - 1][j - 1] + map[i][j];
}
/*
for (int i = 0; i <= 2 * n; ++i)
{
for (int j = 0; j <= 2 * n; ++j)
printf("%5d", sum[i][j]);
printf("\n");
}
*/
scanf("%d", &q);
while (q--)
{
scanf("%d%d%d%d", &lx, &ly, &rx, &ry);
long long ans = query(rx, ry) - query(lx - 1, ry) - query(rx, ly - 1) + query(lx - 1, ly - 1);
printf("%lld\n", ans);
}
}
}