计蒜客16492 building（二分线段树/分块）

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
using namespace std;
const int maxn = 1e5 + 100, maxN = 500;
int B[maxN], Tag[maxN];
int a[maxn];
int n, m, N, L;
void Update(int i){
    if(Tag[i] == -1) return;
    int bl = i*L, br = min(n, (i+1)*L-1);
    for(int j = bl; j <= br; j++) a[j] = Tag[i];
    Tag[i] = -1;
}
void Change(int l, int r, int v){
    for(int i = 0; i < N; i++){
        int bl = i*L, br = min(n, (i+1)*L-1);
        if(l <= bl && br <= r){
            Tag[i] = v;
            B[i] = v;
        } else if(bl <= l && l <= br && bl <= r && r <= br){
            Update(i);
            B[i] = max(B[i], v);
            for(int j = l; j <= r; j++) a[j] = v;
        } else if(bl <= l && l <= br){
            Update(i);
            B[i] = max(B[i], v);
            for(int j = l; j <= br; j++) a[j] = v;
        } else if(bl <= r && r <= br){
            Update(i);
            B[i] = max(B[i], v);
            for(int j = bl; j <= r; j++) a[j] = v;
        }
    }
}

int Findl(int x){
    int bi = x/L;
    int bl = bi*L, br = min(n, (bi+1)*L-1);
    Update(bi);
    for(int i = x-1; i >= bl; i--){
        if(a[i] > a[x]) return i;
    }
    for(int i = bi-1; i >= 0; i--){
        if(B[i] > a[x]){
            bl = i*L, br = min(n, (i+1)*L-1);
            Update(i);
            for(int j = br; j >= bl; j--)
                if(a[j] > a[x]) return j;
        }
    }
    return -1;
}

int Findr(int x){
    int bi = x/L;
    int bl = bi*L, br = min(n, (bi+1)*L-1);
    Update(bi);
    for(int i = x+1; i <= br; i++){
        if(a[i] > a[x]) return i;
    }
    for(int i = bi+1; i < N; i++){
        if(B[i] > a[x]){
            bl = i*L, br = min(n, (i+1)*L-1);
            Update(i);
            for(int j = bl; j <= br; j++)
                if(a[j] > a[x]) return j;
        }
    }
    return -1;
}


int main()
{
    int x, y, z;
    cin>>n;
    for(int i = 1; i <= n; i++){
        scanf("%d", &a[i]);
    }
    L = sqrt(n+0.5);
    N = n/L + 1;
    for(int i = 0; i < N; i++) Tag[i] = -1;
    for(int i = 1; i <= n; i++){
        B[i/L] = max(B[i/L], a[i]);
    }
    cin>>m;
    for(int i = 1; i <= m; i++){
        scanf("%d", &x);
        if(x == 1){
            scanf("%d %d %d", &x, &y, &z);
            Change(x, y, z);
        } else {
            scanf("%d", &x);
            int l = Findl(x), r = Findr(x);
            if(l == -1 || r == -1) printf("-1\n");
            else printf("%d\n", r-l-1);
        }
    }
}