【HDOJ】1166 敌兵布阵

线段树。

#include <stdio.h>

#define maxn 55555

int sums[maxn<<2];

void PushUP(int rt) {
    sums[rt] = sums[rt<<1] + sums[rt<<1|1];
}

void build(int l, int r, int rt) {
    int m;
    if (l == r) {
        scanf("%d", &sums[rt]);
        return ;
    }
    m = (l+r)>>1;
    build(l, m, rt<<1);
    build(m+1, r, rt<<1|1);
    PushUP(rt);
}

void update(int des, int delta, int l, int r, int rt) {
    int m;
    if (l == r) {
        sums[rt] += delta;
        return ;
    }
    m = (l+r)>>1;
    if (des <= m)
        update(des, delta, l, m, rt<<1);
    else
        update(des, delta, m+1, r, rt<<1|1);
    PushUP(rt);
}

int query(int ll, int rr, int l, int r, int rt) {
    int m, val = 0;
    if (ll<=l && rr>=r)
        return sums[rt];

    m = (l+r)>>1;
    if (ll <= m)
        val += query(ll, rr, l, m, rt<<1);
    if (m < rr)
        val += query(ll, rr, m+1, r, rt<<1|1);

    return val;
}

int main() {
    int case_n, n;
    char cmd[10];
    int i, j, k;

    scanf("%d", &case_n);

    for (k=1; k<=case_n; ++k) {
        scanf("%d", &n);
        build(1, n, 1);
        printf("Case %d:
", k);
        while (1) {
            scanf("%*c%s", cmd);
            if (cmd[0] == 'E')
                break;
            scanf("%d %d", &i, &j);
            if (cmd[0] == 'Q')
                printf("%d
", query(i,j,1,n,1));
            else if (cmd[0] == 'A')
                update(i, j, 1, n, 1);
            else
                update(i, -j, 1, n, 1);
        }
    }

    return 0;
}