区间最值线段树

+改max就完事

#include <bits/stdc++.h>
#define MAXN (int)(2e5 + 7)
#define int long long
using namespace std;
int a[MAXN];
int ans;
int w[MAXN << 2];
int lazy[MAXN << 2];
void update(int u)
{
    w[u] = max(w[2 * u] , w[2 * u + 1]);
}
void build(int u, int l, int r)
{
    if (l == r) // 1 element
    {
        w[u] = a[l];
        return;
    }
    // more than 1
    int mid = (l + r) >> 1;
    // left subtree
    build(2 * u, l, mid);
    // right subtree
    build(2 * u + 1, mid + 1, r);
    // update the data of father
    update(u);
}
bool inrange(int L, int R, int l, int r)
{
    //  [  l  ,  [  L  ,  R  ]  ,  r  ]
    return l <= L && R <= r;
}
void maketag(int u, int L, int R, int val)
//当前树节点 维护的区间 修改的值
{
    lazy[u] += val;
    w[u] = max((R - L + 1) ,val);
}
//下方延迟标记
void pushdown(int u, int L, int R)
{
    int mid = (L + R) / 2;
    maketag(2 * u, L, mid, lazy[u]);
    maketag(2 * u + 1, mid + 1, R, lazy[u]);
    lazy[u] = 0; //清空
}
bool outrange(int L, int R, int l, int r) // not outrange means intersect with tree is interval
{
    //  [  l  ,  r  ]  ,  [  L  ,  R  ]  or  [  L  ,  R  ]  ,  [  l  ,  r  ]
    return r < L || R < l;
}
int query(int u, int L, int R, int l, int r)
{
    if (inrange(L, R, l, r)) //包含
    {
        return w[u];
    }
    else if (!outrange(L, R, l, r)) //相交
    {
        pushdown(u, L, R);
        int mid = (L + R) / 2;
        return max(query(2 * u, L, mid, l, r) , query(2 * u + 1, mid + 1, R, l, r));
    }
    else //不相交
    {
        return -(MAXN<<2);
    }
}
void point_add(int u, int L, int R, int x, int y) //单点修改
//当前树节点 维护的区间 修改的位置 增加的值
{
    if (L == R)
    {
        w[u] += y;
        return;
    }
    int mid = (L + R) / 2;
    if (x <= mid)
    {
        point_add(2 * u, L, mid, x, y);
    }
    else
    {
        point_add(2 * u + 1, mid + 1, R, x, y);
    }
    update(u);
}
void addinterval(int u, int L, int R, int l, int r, int val)
{
    if (inrange(L, R, l, r))
    {
        maketag(u, L, R, val);
    }
    else if (!outrange(L, R, l, r))
    {
        pushdown(u, L, R);
        int mid = (L + R) / 2;
        addinterval(2 * u, L, mid, l, r, val);
        addinterval(2 * u + 1, mid + 1, R, l, r, val);
        update(u);
    }
}
signed main()
{
    char c;
    int x,y,n,m;
    scanf("%lld%lld", &n, &m);
    for (int i = 1; i <= n; i++)
    {
        scanf("%lld",&a[i]);
    }
    build(1, 1, n);
    for (int i = 1; i <= m; i++)
    {
        scanf(" %c%lld%lld", &c, &x, &y);
        if (c == 'Q')
        {
            cout<<query(1,1,n,x,y);
        }
        else
        {
            if (query(1,1,n,x,x)<y)
            {
                point_add(1,1,n,x,(y-x));
            }
        }
    }
    return EXIT_SUCCESS;
}