poj1195

二维树状数组

#include <iostream>
#include <cstdlib>
#include <cstring>
#include <cstdio>
using namespace std;

#define maxn 1030

int c[maxn][maxn];
int Row, Col, n;

inline int Lowbit(const int &x)
{
    return x & (-x);
}

int Sum(int i, int j)
{
    int tempj, sum = 0;
    while (i > 0)
    {
        tempj = j;
        while (tempj > 0)
        {
            sum += c[i][tempj];
            tempj -= Lowbit(tempj);
        }
        i -= Lowbit(i);
    }
    return sum;
}

void Update(int i, int j, int num)
{
    int tempj;
    while (i <= Row)
    {
        tempj = j;
        while (tempj <= Col)
        {
            c[i][tempj] += num;
            tempj += Lowbit(tempj);
        }
        i += Lowbit(i);
    }
}

int cal(int l, int b, int r, int t)
{
    return Sum(r, t) - Sum(l, t) - Sum(r, b) + Sum(l, b);
}

int main()
{
    //freopen("t.txt", "r", stdin);
    int order, x, y, a, l, r, b, t;
    while (scanf("%d", &order), order != 3)
    {
        if (order == 0)
        {
            scanf("%d", &n);
            Col = Row = n + 2;
            memset(c, 0, sizeof(c));
        }
        else if (order == 1)
        {
            scanf("%d%d%d", &x, &y, &a);
            Update(x + 2, y + 2, a);
        }
        else if (order == 2)
        {
            scanf("%d%d%d%d", &l, &b, &r, &t);
            printf("%d\n", cal(l + 1, b + 1, r + 2, t + 2));
        }
    }
    return 0;
}