POJ 3468 A Simple Problem with Integers 线段树区间修改

区间增加

区间查询和

struct Tree {
    int l, r;
    ll sum;
};

Tree node[maxn * 4];
ll a[maxn];
ll lazy[maxn * 4];

void Pushdown(int rt, int m) {
    if (lazy[rt]) {
        lazy[rt << 1] += lazy[rt];
        lazy[rt << 1 | 1] += lazy[rt];
        node[rt << 1].sum += lazy[rt] * (m - (m >> 1));
        node[rt << 1 | 1].sum += lazy[rt] * (m >> 1);
        lazy[rt] = 0;
    }
}

void Pushup(int i) {
    node[i].sum = node[i << 1].sum + node[i << 1 | 1].sum;
}

void Build(int i, int l, int r) {
    lazy[i] = 0;
    node[i].l = l;
    node[i].r = r;
    if (l == r) {
        node[i].sum = a[l];
        return;
    }
    int mid = l + r >> 1;
    Build(i << 1, l, mid);
    Build(i << 1 | 1, mid + 1, r);
    Pushup(i);
}

ll getsum(int i, int l, int r) {
    if (node[i].l == l && node[i].r == r) return node[i].sum;
    int mid = node[i].l + node[i].r >> 1;
    Pushdown(i, node[i].r - node[i].l + 1);
    if (r <= mid) return getsum(i << 1, l, r);
    else if (l > mid) return getsum(i << 1 | 1, l, r);
    else return getsum(i << 1, l, mid) + getsum(i << 1 | 1, mid + 1, r);
}

void update(int i, int l, int r, ll v) {
    if (node[i].r == r && node[i].l == l) {
        lazy[i] += v;
        node[i].sum += (ll)v * (r - l + 1);
        return;
    }
    if (node[i].l == node[i].r) return;
    int mid = node[i].l + node[i].r >> 1;
    Pushdown(i, node[i].r - node[i].l + 1);
    if (r <= mid) update(i << 1, l, r, v);
    else if (l > mid) update(i << 1 | 1, l, r, v);
    else {
        update(i << 1, l, mid, v);
        update(i << 1 | 1, mid + 1, r, v);
    }
    Pushup(i);
}

int main() {
    int n, q;
    int l, r;
    char op[3];
    n = readint(), q = readint();
    for (int i = 1; i <= n; i++) a[i] = readll();
    Build(1, 1, n);
    while (q--) {
        scanf("%s", op);
        l = readint(), r = readint();
        if (strcmp(op, "C") == 0) {
            ll val = readll();
            update(1, l, r, val);
        }
        else {
            Put(getsum(1, l, r));
            puts("");
        }
    }
}