杭电 1166 敌兵布阵 1754 I Hate It（线段树）

1166与1754相似（线段树）

1166讲的是对一段区间求和，而1754是对一段区间求最值。套用经典线段树模版

1166代码：

 

#include<iostream>
#include<string>
using namespace std;
struct node
{
    int a,b,sum;
};
node re[140000];
int s,p[50001];
void make(int x,int y,int z)
{
    re[z].a=x;
    re[z].b=y;
    if(x==y)
    {
        re[z].sum=p[y];
        return ;
    }
    make(x,(x+y)/2,z+z);
    make((x+y)/2+1,y,z+z+1);
    re[z].sum=re[z+z].sum+re[z+z+1].sum;
}
void que(int x,int y,int z)
{
    if(x<=re[z].a&&re[z].b<=y)
        s+=re[z].sum;
    else
    {
        if(x>(re[z].a+re[z].b)/2)
            que(x,y,z+z+1);
        else if(y<=(re[z].a+re[z].b)/2)
            que(x,y,z+z);
        else
        {
            que(x,y,z+z);
            que(x,y,z+z+1);        
        }
    }
}
void add(int x,int y,int z)
{
    re[z].sum+=y;
    if(re[z].a==x&&re[z].b==x)
        return;
    if(x>(re[z].a+re[z].b)/2)
        add(x,y,z+z+1);
    else
        add(x,y,z+z);
}
void sub(int x,int y,int z)
{
    re[z].sum-=y;
    if(re[z].a==x&&re[z].b==x)
        return;
    if(x>(re[z].a+re[z].b)/2)
        sub(x,y,z+z+1);
    else
        sub(x,y,z+z);
}
int main()
{
    int t,n;
    int i,j,x,y;
    char c[10];
    cin>>t;
    for(j=1;j<=t;j++)
    {
        cout<<"Case "<<j<<':'<<endl;
        cin>>n;
        for(i=1;i<=n;i++)
            cin>>p[i];
        make(1,n,1);
        while(cin>>c)
        {
            if(strcmp(c,"End")==0)
                break;
            cin>>x>>y;
            if(strcmp(c,"Add")==0)
            {
                add(x,y,1);
            }
            if(strcmp(c,"Sub")==0)
            {
                sub(x,y,1);
            }
            if(strcmp(c,"Query")==0)
            {
                s=0;
                que(x,y,1);
                cout<<s<<endl;
            }
        }
    }
    return 0;
}

 

 

1754代码：（建议用c的输入输出 与 c++相比差了三倍的时间）

 

#include<iostream>
#include<stdlib.h>
#include<algorithm>
#define nsize 200001 
using namespace std;

int s[nsize];
struct node
{
    int a,b,ma;
};
node re[nsize*3];
inline void make(int x,int y,int z)
{
    re[z].a=x;
    re[z].b=y;
    if(x==y)
        re[z].ma=s[x];
    else 
    {
        make(x,(x+y)/2,z+z);
        make((x+y)/2+1,y,z+z+1);
        re[z].ma=max(re[z+z].ma,re[z+z+1].ma);
    }
}
inline void updata(int x,int y,int z)
{
    if(re[z].a==re[z].b)
        re[z].ma=y;
    else
    {
        if(x<=(re[z].a+re[z].b)/2)
            updata(x,y,z+z);
        else
            updata(x,y,z+z+1);
        re[z].ma=max(re[z+z].ma,re[z+z+1].ma);
    }
}
inline int que(int x,int y,int z)
{
    if(re[z].a==x&&re[z].b==y)
    {
        return re[z].ma;
    }
    else
    {
        if(x>(re[z].a+re[z].b)/2)
         return   que(x,y,z+z+1);
        if(y<=(re[z].a+re[z].b)/2)
          return  que(x,y,z+z);
        else
        {
         return   max(que(x,(re[z].a+re[z].b)/2,z+z),que((re[z].a+re[z].b)/2+1,y,z+z+1));
        }
    }
}
int main()
{
    int n,m;
    int i,j,x,y;
    char c;
    while(~scanf("%d%d",&n,&m))
    {
        
        for(i=1;i<=n;i++)
        {
            scanf("%d",&s[i]);
        }   
        make(1,n,1);
        for(j=1;j<=m;j++)
        {   
            scanf("%s %d%d",&c,&x,&y);
            if(c=='Q')
            {
                int zq=que(x,y,1);
                printf("%d\n",zq);
            }    
            else
                updata(x,y,1);
        }
    }
    return 0;
}