hdu 3016线段树之七

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对每一个木板，用线段树去找它左边和右边能到达到的木板的编号：
最后dp：
#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>using namespace std;struct p{    int l;    int r;    int n;    int mark;} tree[444444];struct pp{    int ln;    int rn;    int l;    int r;    int v;    int h;} s[111111];void build(int n,int l,int r){    tree[n].l = l;    tree[n].r = r;    tree[n].mark  =0;    tree[n].n = -1;    if(l == r)        return ;    int mid = (l+r)/2;    build(n*2,l,mid);    build(n*2+1,mid+1,r);}void update(int n,int l,int r,int k){    if(tree[n].l == l&&tree[n].r == r)    {        tree[n].mark = 1;        tree[n].n = k;        return ;    }    int mid = (tree[n].l + tree[n].r)/2;    if(tree[n].mark!=0)    {        tree[n*2].mark = tree[n*2+1].mark = tree[n].mark;        tree[n*2].n = tree[n*2+1].n = tree[n].n;        tree[n].mark=0;    }    if(r<=mid)    {        update(n*2,l,r,k);    }    else if(l>mid)    {        update(n*2+1,l,r,k);    }    else    {        update(n*2,l,mid,k);        update(n*2+1,mid+1,r,k);    }}int query(int n,int x){    if(tree[n].l == tree[n].r)        return tree[n].n;    int mid=(tree[n].l+tree[n].r)/2;    if(tree[n].mark==1)    {        tree[n*2].mark = tree[n*2+1].mark = tree[n].mark;        tree[n*2].n = tree[n*2+1].n = tree[n].n;        return tree[n].n;    }    if(x<=mid)    {        return query(n*2,x);    }    else    {        return query(n*2+1,x);    }}int cmp(pp a, pp b){    return a.h<b.h;}int dp[111111];int main(){    int i,j,k,l,m,n;    while(scanf("%d",&n) == 1)    {        n++;        s[0].h = 0;        s[0].l = 1;        s[0].r = 100000;        s[0].v=0;        for(i = 1; i<n; i++)        {            scanf("%d%d%d%d",&s[i].h,&s[i].l,&s[i].r,&s[i].v);        }        sort(s, s+n, cmp);        build(1, 1, 100000);        memset(dp,0,sizeof(dp));        for(i = 0;i<n; i++)        {            s[i].ln=query(1, s[i].l);            s[i].rn=query(1, s[i].r);           // cout<<s[i].ln<<" "<<s[i].rn<<endl;            update(1, s[i].l, s[i].r, i);        }        dp[n-1]=100+s[n-1].v;        for(i=n-1; i>0; i--)        {            dp[s[i].ln] = max(dp[s[i].ln], dp[i]+s[s[i].ln].v);            dp[s[i].rn] = max(dp[s[i].rn], dp[i]+s[s[i].rn].v);        }        if(dp[0]<=0)        dp[0]=-1;        printf("%d\n",dp[0]);    }    return 0;}
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