hdu 2795 线段树

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=2795

 #include <cstdio>
 #include <cmath>
 #include <algorithm>
 #include <iostream>
 #include <cstring>
 #include <queue>
 #include <vector>

 #define maxn 222222
 #define lson l,mid,u<<1
 #define rson mid+1,r,u<<1|1
 using namespace std;

 const int INF = 0x3f3f3f;
 int h,w,n;
 int seg[maxn<<];
 int row;

 int Push_UP(int u){
     seg[u] = max(seg[u<<],seg[u<<|]);  //****这个地方 u<<1|1 不能换为 u << 1 +1
 }
 void build(int l,int r,int u){
     if(l == r){
          seg[u] = w;
          return;
     }
     int mid = (l + r)>>;
     build(lson);
     build(rson);
     Push_UP(u);
 }
 void Update(int loc,int num,int l,int r,int u){
     if(l == r){  // 这个地方要注意！！
         seg[u] -= num;
         return;
     }
     int mid = (l + r)/;
     if(loc <= mid) Update(loc,num,lson);
     else           Update(loc,num,rson);
     Push_UP(u);
 }

 int Query(int num,int l,int r,int u){
     if(seg[u] < num) return -;

     if(l == r && seg[u] >= num){
         return l;
     }
     int ret = ;
     int mid = (l + r)/;
     ret = Query(num,lson);
     if(ret != -) return ret;
     else          return Query(num,rson);
 }
 int main()
 {
     //if(freopen("input.txt","r",stdin)== NULL)  {printf("Error\n"); exit(0);}
     while(cin>>h>>w>>n){
         if(h > n) h = n;
         build(,h,);
         while(n--){
             int a;
             scanf("%d\n",&a);
             row = Query(a,,h,);
             if(row == -) printf("-1\n");
             else{
                 Update(row,a,,h,);
                 printf("%d\n",row);
             }
         }
     }
 }

参考别人的改进版：

 #include <cstdio>
 #include <cmath>
 #include <algorithm>
 #include <iostream>
 #include <cstring>
 #include <queue>
 #include <vector>

 #define maxn 222222
 #define lson l,mid,u<<1
 #define rson mid+1,r,u<<1|1
 using namespace std;

 const int INF = 0x3f3f3f;
 int h,w,n;
 int seg[maxn<<];

 int Push_UP(int u){
     seg[u] = max(seg[u<<],seg[u<<|]);  //****这个地方 u<<1|1 不能换为 u << 1 +1
 }
 void build(int l,int r,int u){
     if(l == r){
          seg[u] = w;
          return;
     }
     int mid = (l + r)>>;
     build(lson);
     build(rson);
     Push_UP(u);
 }
 int Query(int num,int l,int r,int u){
     if(l == r ){
         seg[u] -= num;
         return l;
     }
     int ret = ;
     int mid = (l + r)/;
     if(seg[u<<] >= num)     ret = Query(num,lson);
     else                     ret = Query(num,rson);
     Push_UP(u);
     return ret;
 }
 int main()
 {
     //if(freopen("input.txt","r",stdin)== NULL)  {printf("Error\n"); exit(0);}
     while(cin>>h>>w>>n){
         if(h > n) h = n;
         build(,h,);
         while(n--){
             int num;
             scanf("%d\n",&num);
             if(seg[]<num)  printf("-1\n");
             else          printf("%d\n",Query(num,,h,));
         }
     }
 }