Salary Inequity

线段树
按照dfs序给每个员工进行标号，那么同一颗子树上的员工编号就是连续的数字，于是查询和修改都能转换成区间操作，套上线段树就好了。

#include <bits/stdc++.h>using namespace std;const int maxn = 1000010;const int maxx = 0x3f3f3f3f;struct Node {    int x, y;    Node() {}    Node(int xx, int yy): x(xx), y(yy) {}};Node F[5*maxn];int a[5*maxn];int fa[maxn], range[maxn], num[maxn];int x, y, n, m, tot;vector<int> G[maxn];void clean(int x, int l, int r) {    F[x].x = a[x] = 0;    F[x].y = maxx;    if (l == r) return;    int mid = (l+r)/2;    clean(x*2, l, mid);    clean(x*2+1, mid+1, r);}void init() {    memset(fa, 0, sizeof(fa));    for (int i = 1; i <= n; i++) G[i].clear();    clean(1, 1, n);    tot = 0;}void dfs(int x) {    num[x] = ++tot;    for (int i = 0; i < G[x].size(); i++) dfs(G[x][i]);    range[x] = tot;}void check(int x) {    F[x].x = max(F[x*2].x, F[x*2+1].x);    F[x].y = min(F[x*2].y, F[x*2+1].y);}void insert(int x, int l, int r, int t, int v) {    if (l == r) {        F[x].x = F[x].y = v;        return;    }    int mid = (l+r)/2;    if (t <= mid) insert(x*2, l, mid, t, v);    else insert(x*2+1, mid+1, r, t, v);    check(x);}void pd(int x, int l, int r) {    if (l == r) a[x] = 0;    if (a[x] != 0) {        F[x*2].x += a[x];        F[x*2+1].x += a[x];        F[x*2].y += a[x];        F[x*2+1].y += a[x];        a[x*2] += a[x];        a[x*2+1] += a[x];        a[x] = 0;    }}void add(int x, int l, int r, int ll, int rr, int v) {    pd(x, l, r);    if (l == ll && r == rr) {        a[x] += v;        F[x].x += v, F[x].y += v;        return;    }    int mid = (l+r)/2;    if (rr <= mid) add(x*2, l, mid, ll, rr, v);    else if (ll > mid) add(x*2+1, mid+1, r, ll, rr, v);    else {        add(x*2, l, mid, ll, mid, v);        add(x*2+1, mid+1, r, mid+1, rr, v);    }    check(x);}Node find(int x, int l, int r, int ll, int rr) {    pd(x, l, r);    if (l == ll && r == rr) {        return F[x];    }    int mid = (l+r)/2;    if (rr <= mid) return find(x*2, l, mid, ll, rr);    else if (ll > mid) return find(x*2+1, mid+1, r, ll, rr);    else {        Node temp1 = find(x*2, l, mid, ll, mid);        Node temp2 = find(x*2+1, mid+1, r, mid+1, rr);        temp1.x = max(temp1.x, temp2.x);        temp1.y = min(temp1.y, temp2.y);        return temp1;    }}char getOP() {    char op = ' ';    while (op != 'Q' && op != 'R') op = getchar();    return op;}int main() {    freopen("input.txt","r",stdin);    int T;    scanf("%d", &T);    while (T--) {        scanf("%d", &n);        init();        for (int i = 2; i <= n; i++) {            scanf("%d", &fa[i]);            G[fa[i]].push_back(i);        }        dfs(1);        for (int i = 1; i <= n; i++) {            scanf("%d", &x);            insert(1, 1, n, num[i], x);        }        scanf("%d", &m);        while (m--) {            char c = getOP();            if  (c == 'Q') {                scanf("%d", &x);                Node temp = find(1, 1, n, num[x], range[x]);                printf("%d\n", temp.x-temp.y);            } else {                scanf("%d %d", &x, &y);                add(1, 1, n, num[x], range[x], y);            }        }    }}