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segment tree lazy propogation

Tame Tapir answered on February 21, 2022 Popularity 9/10 Helpfulness 3/10

answer segment tree lazy propogation

segment tree lazy propogation

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void push(int v) {
    t[v*2] += lazy[v];
    lazy[v*2] += lazy[v];
    t[v*2+1] += lazy[v];
    lazy[v*2+1] += lazy[v];
    lazy[v] = 0;
}

void update(int v, int tl, int tr, int l, int r, int addend) {
    if (l > r) 
        return;
    if (l == tl && tr == r) {
        t[v] += addend;
        lazy[v] += addend;
    } else {
        push(v);
        int tm = (tl + tr) / 2;
        update(v*2, tl, tm, l, min(r, tm), addend);
        update(v*2+1, tm+1, tr, max(l, tm+1), r, addend);
        t[v] = max(t[v*2], t[v*2+1]);
    }
}

int query(int v, int tl, int tr, int l, int r) {
    if (l > r)
        return -INF;
    if (l <= tl && tr <= r)
        return t[v];
    push(v);
    int tm = (tl + tr) / 2;
    return max(query(v*2, tl, tm, l, min(r, tm)), 
               query(v*2+1, tm+1, tr, max(l, tm+1), r));
}

Popularity 9/10 Helpfulness 3/10 Language cpp

Source: cp-algorithms.com

Tags: c++ segment-tree

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