hdu 1166 敌兵布阵

这是一道线段树里最简单的一类题目了，单点更新类型！

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

#include <cstdio>#define lson l , m , rt<<1#define rson m+1 , r , rt<<1|1const int maxx=55555;int sum[maxx<<2];void pushUp(int rt){     sum[rt]=sum[rt<<1]+sum[rt<<1|1];}void build(int l,int r,int rt){if(l==r){scanf("%d",&sum[rt]);return ;}int m=(l+r)>>1;build(lson);build(rson);pushUp(rt);}void update(int p,int add,int l,int r,int rt){if(l==r){         sum[rt]+=add; return ;}int m=(l+r)>>1;if(p<=m)update(p,add,lson);else update(p,add,rson);pushUp(rt);}int query(int L,int R,int l,int r,int rt){if(L<=l && R>=r){return sum[rt];}int m=(l+r)>>1;int ret=0;if(L<=m)ret+=query(L,R,lson);if(R>m)ret+=query(L,R,rson);return ret;}int main(){int cas;scanf("%d",&cas);for(int i=1;i<=cas;i++){printf("Case %d:\n",i);    int n,a,b;scanf("%d",&n);build(1,n,1);while(true){char op[10];scanf("%s",op);if(op[0]=='E')break;scanf("%d%d",&a,&b);if(op[0]=='A')update(a,b,1,n,1);else if(op[0]=='S')update(a,-b,1,n,1);else printf("%d\n",query(a,b,1,n,1));}}return 0;}