線段樹求某值之前或之後與其差值不小於k的最近位置

#include <cstdio>
#include <algorithm>
#include <cstring>
#include <iostream>

using namespace std;
#define maxn 100000 + 10
#define lson L, mid, rt<<1
#define rson mid+1, R, rt<<1|1

int n, k;
int a[maxn];
int ans;

struct Node
{
    int mi, ma;
}T[maxn<<2];

void pushup(int rt)
{
    int l = rt<<1, r = rt<<1|1;
    T[rt].ma = max(T[l].ma, T[r].ma);
    T[rt].mi = min(T[l].mi, T[r].mi);
}

void build(int L, int R, int rt)
{
    if(L == R)
    {
        T[rt].ma = T[rt].mi = a[L];
        return ;
    }
    int mid = (L + R) >> 1;
    build(lson);
    build(rson);
    pushup(rt);
}


///注意樹的節點與區間節點不要混淆
void query(int l, int r, int v, int L, int R, int rt)
{
    if(L == R)
    {
        if(abs(T[rt].mi - v) >= k)
        {
            if(ans == -1 || ans < L)
                ans = L;
        }
        return ;
    }
    int mid = (L + R) >> 1;
    if(r > mid)
        if(abs(T[rt<<1|1].mi - v) >= k || abs(T[rt<<1|1].ma - v) >= k)
        query(l, r, v, rson);
    if(ans == -1 && l <= mid)
        if(abs(T[rt<<1].mi - v) >= k || abs(T[rt<<1].ma - v) >= k)
        query(l, r, v, lson);
}

int d[maxn];
long long sum;

int main()
{
    int t;
    scanf("%d", &t);
    while(t--)
    {
        sum = 1;
        scanf("%d%d", &n, &k);
        for(int i=1; i<=n; i++)
            scanf("%d", &a[i]);
        build(1, n, 1);

        d[1] = 1;
        for(int i=2; i<=n; i++)
        {
            ans = -1;
            query(1, i, a[i], 1, n, 1);
            if(ans == -1)
               d[i] = d[i-1];
            else d[i] = max(d[i-1], ans + 1);
            sum += i - d[i] + 1;
        }
        printf("%I64d\n", sum);
    }
    return 0;
}