BZOJ1562: [NOI2009]变换序列(二分图 匈牙利)

#include<cstdio>
#include<vector>
#include<algorithm>
#include<cstring>
const int INF = 1e9 + 10, MAXN = 1e5 + 10;
using namespace std;
inline int read() {
    char c = getchar(); int x = 0, f = 1;
    while(c < '0' || c > '9') {if(c == '-') f = -1; c = getchar();}
    while(c >= '0' && c <= '9') x = x * 10 + c - '0', c = getchar();
    return x * f;
}
int N;
int a[MAXN];
int match[MAXN], vis[MAXN], cur;
vector<int> v[MAXN];
void AddEdge(int x, int y) {
    v[x].push_back(y); 
    v[y].push_back(x);
}
bool Argue(int x) {
    for(int i = 0; i < v[x].size(); i++) {
        int to = v[x][i];
        if(vis[to] == cur) continue;
        vis[to] = cur; 
        if(match[to] == -1 || Argue(match[to])) {
            match[to] = x;
            return true;
        }
    }
    return false;
}
void Hug() {
    int ans = 0;
    for(int i = N - 1; i >= 0; i--) {
        cur++;
        if(!Argue(i)) {printf("No Answer"); exit(0);}
    }    
    for(int i = 0; i < N; i++) match[match[i + N]] = i;
    for(int i = 0; i < N; i++) printf("%d ", match[i]);
}
main() { 
#ifdef WIN32
    freopen("a.in", "r", stdin);
    freopen("a.out", "w", stdout);
#endif
    memset(match, -1, sizeof(match));
    N = read();
    for(int i = 0; i < N; i++) {
        int x = read();
        AddEdge(i, (i + x) % N + N);
        AddEdge(i, (i - x + N) % N + N);
    }
    for(int i = 0; i < N << 1; i++) sort(v[i].begin(), v[i].end());
    Hug();
}