HDU 4614 Vases and Flowers（线段树+记录区间始末点或乱搞）

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=4614

题目大意：有n个空花瓶，有两种操作：

　　　　　操作①：给出两个数字A,B，表示从第A个花瓶开始插花，插B朵花，输出第一个和最后一个插入的花瓶，如果任意花瓶都已经满了不能插花，则输出“Can not put any one.”。

　　　　　操作②：给出两个数字A,B，表示清空第A~B个花瓶，并输出清空掉的花朵数目。

解题思路：线段树，关于操作②，很简单弄个sum表示区间空花瓶数，计算时清空掉的花朵数=区间长度-sum。

　　　　　关于操作①，有两种解法，第一种就是记录更新每个区间的空花瓶的始末点，这样在插花时可以由此直接获得起点终点。

　　　　　　　　　　　第二种，就是乱搞，查找全空区间（都是空花瓶）然后插花，全空区间起点终点的获得就不用说了吧。复杂度真的是玄学（感觉完全算不出来），还以为会超时的，竟然比解法一还快点。。。

解法一：

 #include<stdio.h>
 #include<algorithm>
 #define LC(a) ((a<<1))
 #define RC(a) ((a<<1)+1)
 #define MID(a,b) ((a+b)>>1)
 using namespace std;
 typedef long long ll;
 const int N = 5e4 + ;

 struct node {
     ll l, r;
     ll sum, Start, End, color;//Start是第一个空花瓶位置，End是最后一个空花瓶位置，color=-1,0,1代表初始化，清空，插花
 }tree[N<<];

 ll leave, Start, sum, End;
 void pushup(ll p) {
     //维护区间空花瓶数量
     tree[p].sum = tree[LC(p)].sum + tree[RC(p)].sum;
     tree[p].color = (tree[LC(p)].color == tree[RC(p)].color ? tree[LC(p)].color : -);
     //维护空花瓶起点和终点
     if (tree[LC(p)].Start != )
         tree[p].Start = tree[LC(p)].Start;
     else if (tree[LC(p)].End != )
         tree[p].Start = tree[LC(p)].End;
     else if (tree[RC(p)].Start != )
         tree[p].Start = tree[RC(p)].Start;
     else if (tree[RC(p)].End != )
         tree[p].Start = tree[RC(p)].End;
     else
         tree[p].Start = ;
     tree[p].End = max(max(tree[LC(p)].Start, tree[LC(p)].End), max(tree[RC(p)].Start, tree[RC(p)].End));
 }

 void pushdown(ll p) {
     if (tree[p].color == ) {
         tree[LC(p)].sum = tree[LC(p)].r - tree[LC(p)].l + ;
         tree[LC(p)].Start = tree[LC(p)].l;
         tree[LC(p)].End = tree[LC(p)].r;
         tree[RC(p)].sum = tree[RC(p)].r - tree[RC(p)].l + ;
         tree[RC(p)].Start = tree[RC(p)].l;
         tree[RC(p)].End = tree[RC(p)].r;
         tree[LC(p)].color = tree[RC(p)].color = ;
     }
     else if (tree[p].color == ) {
         tree[LC(p)].sum = tree[LC(p)].Start = tree[LC(p)].End = tree[RC(p)].sum = tree[RC(p)].Start = tree[RC(p)].End = ;
         tree[LC(p)].color = tree[RC(p)].color = ;
     }
 }

 void build(ll p, ll l, ll r) {
     tree[p].l = l;
     tree[p].r = r;
     tree[p].Start = tree[p].End = ;
     tree[p].sum = ;
     if (l == r) {
         tree[p].Start = tree[p].End = l;
         tree[p].sum = ;
         tree[p].color = -;
         return;
     }
     build(LC(p), l, MID(l, r));
     build(RC(p), MID(l, r) + , r);
     pushup(p);
 }
 //清空
 void update(ll p, ll l, ll r) {
     if (r<tree[p].l || l>tree[p].r)
         return;
     if (l <= tree[p].l&&r >= tree[p].r) {
         sum += (tree[p].r - tree[p].l +  - tree[p].sum);
         tree[p].Start = tree[p].l;
         tree[p].End = tree[p].r;
         tree[p].sum = tree[p].r - tree[p].l + ;
         tree[p].color = ;
         return;
     }
     pushdown(p);
     update(LC(p), l, r);
     update(RC(p), l, r);
     pushup(p);
 }
 //插花
 void query(ll p, ll l, ll r) {
     if (r<tree[p].l || l>tree[p].r)
         return;
     if (leave ==  || tree[p].sum == )
         return;
     if (l <= tree[p].l&&r >= tree[p].r) {
         if (Start == )
             Start = tree[p].Start;
         if (leave >= tree[p].sum) {
             leave -= tree[p].sum;
             End = max(End, tree[p].End);
             tree[p].sum = tree[p].Start = tree[p].End = ;
             tree[p].color = ;
             return;
         }
     }
     pushdown(p);
     query(LC(p), l, r);
     query(RC(p), l, r);
     pushup(p);
 }
 int main() {
     ll q;
     scanf("%I64d",&q);
     while (q--) {
         ll n, m;
         scanf("%I64d %I64d",&n,&m);
         build(, , n);
         while (m--) {
             ll k;
             scanf("%I64d",&k);
             //插花
             if (k == ) {
                 ll a, f;
                 scanf("%I64d %I64d",&a,&f);
                 End = Start = ;
                 leave = f;
                 query(, a + , n);
                 if (Start == )
                     printf("Can not put any one.\n");
                 else
                     printf("%I64d %I64d\n",Start-,End-);
             }
             //清空
             else {
                 ll a, b;
                 scanf("%I64d %I64d",&a,&b);
                 sum = ;
                 update(, a + , b + );
                 printf("%I64d\n",sum);
             }
         }
         printf("\n");
     }
     return ;
 }

解法二：

 #include<cstdio>
 #include<cmath>
 #include<cstring>
 #include<iostream>
 #include<algorithm>
 #include<vector>
 #include<queue>
 #include<set>
 #include<map>
 #include<string>
 #define LC(a) (a<<1)
 #define RC(a) (a<<1|1)
 #define MID(a,b) ((a+b)>>1)
 using namespace std;
 typedef long long LL;
 const int INF=0x3f3f3f3f;
 const int N=5e4+;

 int ans,x,Start,End,flag;

 struct node{
     int sum,l,r;//sum表示空花瓶数
 }tree[*N];

 void pushdown(int p){
     //全满
     if(tree[p].sum==tree[p].r-tree[p].l+){
         tree[LC(p)].sum=tree[LC(p)].r-tree[LC(p)].l+;
         tree[RC(p)].sum=tree[RC(p)].r-tree[RC(p)].l+;
     }
     //全空
     else if(tree[p].sum==)
         tree[LC(p)].sum=tree[RC(p)].sum=;
 }

 void pushup(int p){
     tree[p].sum=tree[LC(p)].sum+tree[RC(p)].sum;
 }

 void build(int p,int l,int r){
     tree[p].l=l;
     tree[p].r=r;
     if(l==r){
         tree[p].sum=;
         return;
     }
     build(LC(p),l,MID(l,r));
     build(RC(p),MID(l,r)+,r);
     pushup(p);
 }

 void update(int p,int l,int r){
     if(l>tree[p].r||r<tree[p].l)
         return;
     if(x<=)
         return;
     if(l<=tree[p].l&&r>=tree[p].r){
         if(tree[p].sum==)
             return;
         //找到全空区间
         if(x>=tree[p].sum&&tree[p].sum==tree[p].r-tree[p].l+){
             if(flag==){
                 Start=tree[p].l;
                 flag++;
             }
             x-=tree[p].sum;
             tree[p].sum=;
             End=tree[p].r;
             return;
         }
     }
     pushdown(p);
     update(LC(p),l,r);
     update(RC(p),l,r);
     pushup(p);
 }

 void query(int p,int l,int r){
     if(l>tree[p].r||r<tree[p].l)
         return;
     if(l<=tree[p].l&&r>=tree[p].r){
         ans+=tree[p].r-tree[p].l+-tree[p].sum;
         tree[p].sum=tree[p].r-tree[p].l+;
         return;
     }
     pushdown(p);
     query(LC(p),l,r);
     query(RC(p),l,r);
     pushup(p);
 }

 int main(){
     int T;
     scanf("%d",&T);
     while(T--){
         int n,q;
         scanf("%d%d",&n,&q);
         build(,,n-);
         while(q--){
             int op;
             scanf("%d",&op);
             if(op==){
                 int l;
                 scanf("%d%d",&l,&x);
                 flag=;
                 update(,l,n-);
                 if(flag==)
                     printf("Can not put any one.\n");
                 else
                     printf("%d %d\n",Start,End);
             }
             else{
                 int l,r;
                 scanf("%d%d",&l,&r);
                 ans=;
                 query(,l,r);
                 printf("%d\n",ans);
             }
         }
         printf("\n");
     }
     return ;
 }