2015暑假训练赛个人赛（7.31）

  1 #include <cstdio>
  2 #include <vector>
  3 #include <cstring>
  4 #include <queue>
  5 
  6 using namespace std;
  7 const int maxv = 1e+4;
  8 const int maxe = 1e+6;;
  9 const long long INF = 0x3f3f3f3f;
 10 
 11 struct Edge {
 12     int from, to, cap, flow, cost;
 13     Edge() {}
 14     Edge(int from, int to, int cap, int flow, int cost) {
 15         this->from = from;
 16         this->to = to;
 17         this->cap = cap;
 18         this->flow = flow;
 19         this->cost = cost;
 20     }
 21 };
 22 struct MCMF {
 23     int n, m, s, t;
 24     vector<Edge> edges;
 25     vector<int> G[maxv];
 26     int inq[maxe];
 27     int d[maxe];
 28     int p[maxe];
 29     int a[maxe];
 30 
 31     void init(int n) {
 32         this -> n = n;
 33         for (int i = 0; i < n; i++) G[i].clear();
 34         edges.clear();
 35     }
 36     void AddEdge(int from, int to, int cap, int cost) {
 37         edges.push_back(Edge(from, to, cap, 0, cost));
 38         edges.push_back(Edge(to, from, 0, 0, -cost));
 39         m = edges.size();
 40         G[from].push_back(m-2);
 41         G[to].push_back(m-1);
 42     }
 43 
 44     bool BellmanFord(int s, int t, int &flow, int &cost) {
 45         for (int i = 0; i < n; i++) d[i] = INF;
 46         memset(inq, 0, sizeof(inq));
 47         d[s] = 0; inq[s] = 1; p[s] = 0; a[s] = INF;
 48 
 49         queue<int>Q;
 50         Q.push(s);
 51         while (!Q.empty()) {
 52             int u = Q.front(); Q.pop();
 53             inq[u] = 0;
 54             for (int i = 0; i < (int)G[u].size(); i++) {
 55                 Edge &e = edges[G[u][i]];
 56                 if (e.cap > e.flow && d[e.to] > d[u] + e.cost) {
 57                     d[e.to] = d[u] + e.cost;
 58                     p[e.to] = G[u][i];
 59                     a[e.to] = min(a[u], e.cap - e.flow);
 60                     if (!inq[e.to]) {Q.push(e.to); inq[e.to] = 1;}
 61                 }
 62             }
 63         }
 64         if (d[t] == INF) return false;
 65         flow += a[t];
 66         cost += d[t] * a[t];
 67         int u = t;
 68         while (u != s) {
 69             edges[p[u]].flow += a[t];
 70             edges[p[u]^1].flow -= a[t];
 71             u = edges[p[u]].from;
 72         }
 73         return true;
 74     }
 75 
 76     int Mincost (int s, int t) {
 77         int flow = 0, cost = 0;
 78         while (BellmanFord(s, t, flow, cost));
 79         return flow;
 80     }
 81 }G;
 82 
 83 char S[1000], tep[10];
 84 int vis[26+10], num[26+10];
 85 
 86 int main() {
 87     int t;
 88     freopen("in.txt", "r", stdin);
 89     scanf("%d", &t);
 90     while (t--) {
 91         scanf("%s", S);
 92         int lenS = strlen(S);
 93         int s = lenS+26, t = lenS + 27;
 94         G.init(t+2);
 95         memset(num, 0, sizeof(num));
 96         for (int i = 0; i < lenS; i++) {
 97             num[S[i] - ‘a‘]++;
 98             G.AddEdge(s, i, 1, 0);
 99         }
100 
101         for (int i = 0 ; i < lenS; i++) {
102             scanf("%s", tep);
103             int lentep = strlen(tep);
104             memset(vis, 0, sizeof(vis));
105             for (int j = 0; j < lentep; j++) {
106                 vis[tep[j] - ‘a‘]++;
107             }
108             for (int j = 0; j < 26; j++) {
109                 if (vis[j]) {
110                     G.AddEdge(i, lenS+j, vis[j], 10*i + 1000*j);
111                 }
112             }
113         }
114         for (int i = 0; i < 26; i++) {
115             G.AddEdge(lenS+i, t, num[i], 0);
116         }
117         if (G.Mincost(s, t) < lenS) {
118             puts("NO SOLUTION");
119         } else {
120             for (int i = 0; i < (int)G.edges.size(); i += 2) {
121                 int u = G.edges[i].from;
122                 int v = G.edges[i].to;
123                 int flow = G.edges[i].flow;
124                 int cost = G.edges[i].cost;
125                 int cap = G.edges[i].cap;
126                 //printf("%d %d (%d %d) %d\n", u, v, flow, cap, cost);
127                 if (lenS <= v && v < lenS + 26 && flow > 0)
128                 printf("%c", ‘a‘ + v - lenS);
129             }
130             puts("");
131         }
132     }
133     return 0;
134 }