hdu1166 敌兵布阵

http://acm.hdu.edu.cn/showproblem.php?pid=1166

线段树，单点更新

#include <stdio.h>

#define lson l, m, root<<1
#define rson m+1, r, root<<1|1

const int maxn = 55555;

int sum[maxn<<2];

void push_up(int root)
{
    sum[root] = sum[root<<1] + sum[root<<1|1];
}

void build(int l, int r, int root)
{
    int m = (l + r) >> 1;
    if(l == r)
    {
        scanf("%d", sum+root);
        return;
    }
    build(lson);
    build(rson);
    push_up(root);
}

void update(int x, int add, int l, int r, int root)
{
    int m = (l + r) >> 1;
    if(l == r)
    {
        sum[root] += add;
        return;
    }
    if(x <= m)
    {
        update(x, add, lson);
    }
    if(m+1 <= x)
    {
        update(x, add, rson);
    }
    push_up(root);
}

int query(int L, int R, int l, int r, int root)
{
    int m = (l + r) >> 1, result = 0;
    if(L <= l && r <= R)
    {
        return sum[root];
    }
    if(L <= m)
    {
        result += query(L, R, lson);
    }
    if(m+1 <= R)
    {
        result += query(L, R, rson);
    }
    return result;
}

int main()
{
    int t, cases, n, a, b;
    char s[8];
    scanf("%d", &t);
    for(cases=1; cases<=t; cases++)
    {
        printf("Case %d:\n", cases);
        scanf("%d", &n);
        build(1, n, 1);
        while(scanf("%s", s), s[0]-'E')
        {
            scanf("%d%d", &a, &b);
            if(s[0] == 'Q')
            {
                printf("%d\n", query(a, b, 1, n, 1));
                continue;
            }
            if(s[0] == 'A')
            {
                update(a, b, 1, n, 1);
            }
            else
            {
                update(a, -b, 1, n, 1);
            }
        }
    }
    return 0;
}