BZOJ2054 疯狂的馒头

还是离线把操作倒过来做，于是每个馒头只要看最后一种颜色就好了

如果一个馒头已经有颜色了，就把它并到右边的馒头的集合里去

/**************************************************************
    Problem: 2054
    User: rausen
    Language: C++
    Result: Accepted
    Time:3268 ms
    Memory:39776 kb
****************************************************************/
 
#include <cstdio>
#include <algorithm>
 
using namespace std;
const int N = 1e6 + 5;
 
int c[N], fa[N];
int n, m, p, q;
 
int find_f(int x) {
    return x == fa[x] ? x : fa[x] = find_f(fa[x]);
}
 
int main() {
    int i, j, x, y;
    scanf("%d%d%d%d", &n, &m, &p, &q);
    for (i = 1; i <= n + 1; ++i) fa[i] = i;
    for (i = m; i; --i) {
        x = (1ll * i * p + q) % n + 1, y = (1ll * i * q + p) % n + 1;
        if (x > y) swap(x, y);
        for (j = find_f(x); j <= y; j = find_f(j))
            c[j] = i, fa[j] = j + 1;
    }
    for (i = 1; i <= n; ++i)
        printf("%d
", c[i]);
    return 0;
}