HDU

HDU - 1698 http://acm.hdu.edu.cn/showproblem.php?pid=1698
思路：区间更新 直接整段区间求和

#include <cstdio>#include <iostream>#include <cstring>#include <algorithm>using namespace std;const int maxn = 100000 + 10;int n,m;struct node{    int v,ltag,l,r,len;}tree[maxn << 2];void iset(int id,int l,int r){    tree[id].l = l; tree[id].r = r;    tree[id].ltag = 0;    tree[id].v = 1;    tree[id].len = r-l+1;}int btree(int l,int r,int id){    iset(id,l,r);    if(l == r) return tree[id].v;    int mid  = l+r>>1;    btree(l,mid,id<<1);    btree(mid+1,r,id<<1|1);    return tree[id].v = tree[id<<1].v + tree[id<<1|1].v;}void uselazy(int lazy,int id){    tree[id].ltag = lazy;    tree[id].v = lazy*tree[id].len;}int pushtag(int id){    int k = id;    int lazy = tree[id].ltag;    if(lazy)    {        uselazy(lazy,id<<1);        uselazy(lazy,id<<1|1);        tree[k].ltag = 0;    }    return 0;}int updata(int ql,int qr,int v,int id){    int l = tree[id].l, r = tree[id].r;    if(l == ql && r == qr) {tree[id].ltag = v; return tree[id].v = v*tree[id].len;}    pushtag(id);    int mid = l+r>>1;    if(qr <= mid)   updata(ql,qr,v,id<<1);    else if(ql > mid)   updata(ql,qr,v,id<<1|1);    else    updata(ql,mid,v,id<<1), updata(mid+1,qr,v,id<<1|1);    return tree[id].v = tree[id<<1].v + tree[id<<1|1].v;}int main(){    int t;    scanf("%d",&t);    for(int kase = 1; kase <= t; kase ++)    {        scanf("%d%d",&n,&m);        btree(1,n,1);        for(int i = 0; i < m ; i++)        {            int a,b,v;            scanf("%d%d%d",&a,&b,&v);            updata(a,b,v,1);        }        printf("Case %d: The total value of the hook is %d.\n",kase,tree[1].v);    }    return 0;}