线段树练习1

题意

n个数，m次操作，每次询问区间第k大，或者给区间加上一个数。

$数据范围：1 ≤ n,m ≤ 10^5 ,1 ≤ k ≤ 10。$

 

题解

由于k很小，直接在线段树内维护，前k大的数。

 

code

  1 #include<cstdio>
  2 #include<cstring>
  3 
  4 #define lson l,m,rt<<1
  5 #define rson m+1,r,rt<<1|1
  6 
  7 #define N 100010
  8 #define K 10
  9 
 10 int n,m;
 11 struct Tree {
 12     int data[K];
 13     Tree() {memset(data,0,sizeof(data));}
 14     Tree operator + (const Tree &a) const {
 15         Tree ret;
 16         int p1 = 0,p2 = 0;
 17         for (int i=0; i<K; ++i) 
 18             if (data[p1] > a.data[p2]) ret.data[i] = data[p1++];
 19             else ret.data[i] = a.data[p2++];
 20         return ret;
 21     }
 22 }t[N<<2];
 23 int a[N],tag[N<<2];
 24 
 25 inline int read() {
 26     int x = 0,f = 1;char ch = getchar();
 27     for (; ch<'0'||ch>'9'; ch = getchar())
 28         if (ch=='-') f = -1;
 29     for (; ch>='0'&&ch<='9'; ch = getchar())
 30         x = x*10+ch-'0';
 31     return x*f;
 32 }
 33 
 34 inline void pushup(int rt) {
 35     t[rt] = t[rt<<1] + t[rt<<1|1];
 36 }
 37 inline void pushdown(int rt) {
 38     if (tag[rt]) {
 39         tag[rt<<1] += tag[rt];
 40         for (int i=0; i<K; ++i) 
 41             if (t[rt<<1].data[i]) t[rt<<1].data[i] += tag[rt];//只加有的数字 
 42         tag[rt<<1|1] += tag[rt];
 43         for (int i=0; i<K; ++i) 
 44             if (t[rt<<1|1].data[i]) t[rt<<1|1].data[i] += tag[rt];
 45         tag[rt] = 0;
 46     }
 47 }
 48 void build(int l,int r,int rt) {
 49     if (l==r) {
 50         t[rt].data[0] = a[l];
 51         return ;
 52     } 
 53     int m = (l+r) >> 1;
 54     build (lson);
 55     build (rson);
 56     pushup(rt);
 57 }
 58 void update(int l,int r,int rt,int L,int R,int c) {
 59     if (L <= l && r <= R) {
 60         tag[rt] += c;
 61         for (int i=0; i<K; ++i) 
 62             if (t[rt].data[i]) t[rt].data[i] += c;
 63         return ;
 64     }
 65     pushdown(rt);
 66     int m = (l+r) >> 1;
 67     if (L <= m) update(lson,L,R,c);
 68     if (R > m)  update(rson,L,R,c);
 69     pushup(rt);
 70 }
 71 Tree query(int l,int r,int rt,int L,int R) {
 72     if (L <= l && r <= R) {
 73         return t[rt];
 74     }
 75     pushdown(rt);
 76     Tree ret;
 77     int m = (l+r) >> 1;
 78     if (L <= m) ret = ret + query(lson,L,R);
 79     if (R > m)  ret = ret + query(rson,L,R);
 80     return ret ;
 81 }
 82 int main() {
 83     
 84     int n = read(),m = read();
 85     for (int i=1; i<=n; ++i) a[i] = read();
 86     build(1,n,1);
 87     Tree ans;
 88     while (m--) {
 89         int opt = read(),l = read(),r = read(),k = read();
 90         if (opt==0) {
 91             if (r-l+1 < k) puts("-1");
 92             else {
 93                 ans = query(1,n,1,l,r);
 94                 printf("%d\n",ans.data[k-1]);
 95             }
 96         }
 97         else update(1,n,1,l,r,k);
 98     }
 99     return 0;
100 }

 

by zhx p106 无题

posted @ 2017-11-06 10:16  MJT12044  阅读(215)  评论(0)  编辑  收藏  举报