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

#include<cstdio>
#include<cstring>

#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1

#define N 100010
#define K 10

int n,m;
struct Tree {
int data[K];
Tree() {memset(data,0,sizeof(data));}
Tree operator + (const Tree &a) const {
Tree ret;
int p1 = 0,p2 = 0;
for (int i=0; i<K; ++i)
if (data[p1] > a.data[p2]) ret.data[i] = data[p1++];
else ret.data[i] = a.data[p2++];
return ret;
}
}t[N<<2];
int a
,tag[N<<2];

inline int read() {
int x = 0,f = 1;char ch = getchar();
for (; ch<'0'||ch>'9'; ch = getchar())
if (ch=='-') f = -1;
for (; ch>='0'&&ch<='9'; ch = getchar())
x = x*10+ch-'0';
return x*f;
}

inline void pushup(int rt) {
t[rt] = t[rt<<1] + t[rt<<1|1];
}
inline void pushdown(int rt) {
if (tag[rt]) {
tag[rt<<1] += tag[rt];
for (int i=0; i<K; ++i)
if (t[rt<<1].data[i]) t[rt<<1].data[i] += tag[rt];//只加有的数字
tag[rt<<1|1] += tag[rt];
for (int i=0; i<K; ++i)
if (t[rt<<1|1].data[i]) t[rt<<1|1].data[i] += tag[rt];
tag[rt] = 0;
}
}
void build(int l,int r,int rt) {
if (l==r) {
t[rt].data[0] = a[l];
return ;
}
int m = (l+r) >> 1;
build (lson);
build (rson);
pushup(rt);
}
void update(int l,int r,int rt,int L,int R,int c) {
if (L <= l && r <= R) {
tag[rt] += c;
for (int i=0; i<K; ++i)
if (t[rt].data[i]) t[rt].data[i] += c;
return ;
}
pushdown(rt);
int m = (l+r) >> 1;
if (L <= m) update(lson,L,R,c);
if (R > m)  update(rson,L,R,c);
pushup(rt);
}
Tree query(int l,int r,int rt,int L,int R) {
if (L <= l && r <= R) {
return t[rt];
}
pushdown(rt);
Tree ret;
int m = (l+r) >> 1;
if (L <= m) ret = ret + query(lson,L,R);
if (R > m)  ret = ret + query(rson,L,R);
return ret ;
}
int main() {

int n = read(),m = read();
for (int i=1; i<=n; ++i) a[i] = read();
build(1,n,1);
Tree ans;
while (m--) {
int opt = read(),l = read(),r = read(),k = read();
if (opt==0) {
if (r-l+1 < k) puts("-1");
else {
ans = query(1,n,1,l,r);
printf("%d\n",ans.data[k-1]);
}
}
else update(1,n,1,l,r,k);
}
return 0;
}

by zhx p106 无题