HDU - 1166 敌兵布阵

Posted 2020-12-19 zzhzzh123

题目链接

维护一个单点修改，区间查询的数据结构，树状数组和线段树均可以。

我写了树状数组。

#include<bits/stdc++.h>
using namespace std;

#define lowbit(x) (x & (-x))

char s[10];
int n;
long long c[50005];
void update(int x,long long y){
    for(int i = x; i <= n; i += lowbit(i)) c[i] += y;
}
long long query(int x){
    long long ret = 0;
    for(int i = x; i > 0; i -= lowbit(i)) ret += c[i];
    return ret;
}

int main(){
    int T; scanf("%d",&T);
    for(int cas = 1; cas <= T; ++ cas){
        printf("Case %d:
",cas);
        
        scanf("%d",&n);
        memset(c,0,sizeof(c));
        
        for(int i = 1; i <= n; ++ i){
            int x; scanf("%d",&x);
            update(i,x);
        }
        
        while(1){
            scanf(" %s",s);
            if(s[0] == ‘E‘) break;
            if(s[0] == ‘Q‘){
                int l,r; scanf("%d%d",&l,&r);
                printf("%lld
",query(r) - query(l - 1));
            }
            if(s[0] == ‘A‘){
                int x,y; scanf("%d%d",&x,&y);
                update(x,y);
            }
            if(s[0] == ‘S‘){
                int x,y; scanf("%d%d",&x,&y);
                update(x,-y);
            }
        }
    }
    return 0;
}