HDU:1166 敌兵布阵

来源：互联网发布：qt creator linux 编辑：程序博客网时间：2024/05/16 13:54

之前用树状数组过掉了，这次用线段树重写了一遍，和求区间最值的那代码基本一样。。

#include <iostream>#include <cstdlib>#include <cstdio>#include <cstring>#include <cmath>#include <queue>#include <vector>#include <map>#include <stack>#include <algorithm>#define MAXN 200005#define MOD 1000000007#define INF -2139062144#define ll long long//ios::sync_with_stdio(false)using namespace std;const int MAXN_N = 1<< 19;int sum[2*MAXN_N],mxn,N;void Init(){    mxn=1;    while(mxn<N) mxn*=2;    memset(sum,0,sizeof(sum));}void update(int k,int val){    k+=mxn-1;    sum[k]+=val;    while(k/2>0)    {        k=k/2;        sum[k]+=val;    }}int Query(int a,int b,int k,int l,int r){    if(r<a||b<l) return 0;    if(a<=l&&r<=b) return sum[k];    else    {        int v1=Query(a,b,2*k,l,(l+r)/2);        int v2=Query(a,b,2*k+1,(l+r)/2+1,r);        return v1+v2;    }}int main(){    int T,kase=0;    scanf("%d",&T);    while(T--)    {        scanf("%d",&N);        Init();        for(int i=1; i<=N; ++i)        {            int t;            scanf("%d",&t);            update(i,t);        }        char str[10];        printf("Case %d:\n",++kase);        while(scanf("%s",str))        {            if(str[0]=='E') break;            int a,b;            scanf("%d%d",&a,&b);            if(str[0]=='Q')                printf("%d\n",Query(a,b,1,1,mxn));            else if(str[0]=='A')                update(a,b);            else update(a,-b);        }    }    return 0;}

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