codeforces 150C Smart Cheater 线段树区间合并

分析：题目意思中是针对每位乘客，可以选取一连续段不收票。问题转化为，m次询问，查找区间[a,b)内最大连续子序列和。

#include<cstdio>  
#define ll long long  
#define lson l,m,rt<<1  
#define rson m+1,r,rt<<1|1  
const int N=150002;  
template<class T>  
inline void scan_d(T &ret){  
    char c;ret=0;  
    while((c=getchar())<'0'||c>'9');  
    while(c>='0'&&c<='9')ret=ret*10+(c-'0'),c=getchar();  
}  
struct node{  
    ll s,l,r,m;  
}A[N<<2];  
int x[N];  
ll max(ll a,ll b){return a>b?a:b;}  
node pushup(node L,node R){  
    node F;  
    F.s=L.s+R.s;  
    F.l=max(L.l,L.s+R.l);  
    F.r=max(R.r,L.r+R.s);  
    F.m=max(max(L.m,R.m),L.r+R.l);  
    return F;  
}  
void build(int l,int r,int rt){  
    if(l==r){A[rt].s=A[rt].l=A[rt].r=A[rt].m=x[l];return ;}  
    int m=(l+r)>>1;  
    build(lson);  
    build(rson);  
    A[rt]=pushup(A[rt<<1],A[rt<<1|1]);  
}  
node query(int L,int R,int l,int r,int rt){  
    if(L<=l&&R>=r)return A[rt];  
    int m=(l+r)>>1;  
    if(R<=m)return query(L,R,lson);  
    if(m<L)return query(L,R,rson);  
    node nl=query(L,m,lson),nr=query(m+1,R,rson);  
    return pushup(nl,nr);  
}  
int main(){  
    int n,m,c,i,a,b,p;  
    while(~scanf("%d%d%d",&n,&m,&c)){  
        for(i=1;i<=n;i++)scan_d(x[i]),x[i-1]=(x[i]-x[i-1])*50;  
        for(i=1;i<n;i++)scan_d(p),x[i]-=p*c;n--;  
        build(1,n,1);  
        ll ans=0,t;  
        while(m--){  
            scan_d(a),scan_d(b);  
            t=query(a,b-1,1,n,1).m;  
            if(t>0)ans+=t;  
        }  
        printf("%.8lf\n",ans*0.01);  
    }  
    return 0;  
}