https://www.luogu.org/problemnew/show/P3870

線段樹區間翻轉 + 區間查詢

#include <iostream>
#include <cstdio>
#include <cmath>
#include <algorithm>

using namespace std;
const int N = 1e5 + 10;

#define yxy getchar()
#define lson jd << 1
#define rson jd << 1 | 1

#define
 
 RR freopen("gg.in", "r", stdin)

int n, Ty, ans;
int L[N << 2], R[N << 2], life[N << 2], F[N << 2], size[N << 2];

inline int read() {
    int x = 0, f = 1; char c = yxy;
    while(c < ‘0‘ || c > ‘9‘) {if(c == ‘-‘) f = -1; c = yxy;}
    while(c >= ‘0‘ && c <= ‘
 
9‘) x = x * 10 + c - ‘0‘, c = yxy;
    return x * f;
}

void Build_tree(int l, int r, int jd) {
    L[jd] = l; R[jd] = r; size[jd] = r - l + 1;
    if(l == r) return ;
    int mid = (l + r) >> 1;
    Build_tree(l, mid, lson);
    Build_tree(mid + 1, r, rson);
}

void down(int jd) {
    F[lson] 
 
+= (F[jd] % 2); F[rson] += (F[jd] % 2);
    if(F[jd] % 2) life[lson] = size[lson] - life[lson], life[rson] = size[rson] - life[rson];
    F[jd] = 0;
}

void Sec_G(int l, int r, int jd, int x, int y) {
    if(x <= l && r <= y) {
        F[jd] ++; life[jd] = size[jd] - life[jd]; return ;
    } 
    if(F[jd]) down(jd);
    int mid = (l + r) >> 1;
    if(x <= mid) Sec_G(l, mid, lson, x, y);
    if(y > mid)  Sec_G(mid + 1, r, rson, x, y);
    life[jd] = life[lson] + life[rson]; 
}

void Sec_A(int l, int r, int jd, int x, int y) {
    if(x <= l && r <= y) {
        ans += life[jd]; return ;
    }
    if(F[jd]) down(jd);
    int mid = (l + r) >> 1;
    if(x <= mid) Sec_A(l, mid, lson, x, y);
    if(y > mid) Sec_A(mid + 1, r, rson, x, y);
}

int main() {
    n = read();
    Ty = read();
    Build_tree(1, n, 1);
    while(Ty --) {
        int opt = read(), x = read(), y = read();
        if(!opt) { // 區間翻轉
            Sec_G(1, n, 1, x, y);
        } else {
            ans = 0;
            Sec_A(1, n, 1, x, y);
            cout << ans << endl;
        } 
    }
    return 0;
}

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