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使用KM算法提升速度
#include #include #include #include #include #include #define REP(i,n) for (int i = 1; i <= (n); i++)#define mp(a,b) make_pair (a,b)#define cls(s) memset(s,0,sizeof(s))#define pr pair #define LL long long intusing namespace std;const int maxn = 85,maxm = 100005,INF = 1000000000;inline int read(){ int out = 0,flag = 1; char c = getchar(); while (c < 48 || c > 57){if (c == '-') flag = -1; c = getchar();} while (c >= 48 && c <= 57){out = (out << 3) + (out << 1) + c - 48; c = getchar();} return out * flag;}int w[maxn][maxn],expa[maxn],expb[maxn],dl[maxn],cp[maxn],visa[maxn],visb[maxn];int n,tcp[maxn],mv,ansi;pr ans[maxn];bool dfs(int u){ visa[u] = true; REP(i,n) if (!visb[i]){ int kl = expa[u] + expb[i] - w[u][i]; if (!kl){ visb[i] = true; if (!cp[i] || dfs(cp[i])){ cp[i] = u; return true; } } else dl[i] = min(dl[i],kl); } return false;}inline int work(){ REP(i,n) expa[i] = expb[i] = cp[i] = 0; REP(i,n) REP(j,n) expa[i] = max(expa[i],w[i][j]); REP(i,n){ REP(j,n) dl[j] = INF; while (true){ REP(j,n) visa[j] = visb[j] = false; if (dfs(i)) break; int kl = INF; REP(j,n) if (!visb[j]) kl = min(kl,dl[j]); REP(j,n){ if (visa[j]) expa[j] -= kl; if (visb[j]) expb[j] += kl; else dl[j] -= kl; } } } int re = 0; REP(i,n) re += w[cp[i]][i]; return re;}int main(){ n = read(); REP(i,n) REP(j,n) w[i][j] = read(); mv = work(); printf("%d\n",mv); REP(i,n) tcp[i] = cp[i]; REP(i,n){ int tmp = w[tcp[i]][i]; w[tcp[i]][i] = 0; if (work() < mv) ans[++ansi] = mp(tcp[i],i); w[tcp[i]][i] = tmp; } sort(ans + 1,ans + 1 + ansi); REP(i,ansi) printf("%d %d\n",ans[i].first,ans[i].second); return 0;}
转载于:https://www.cnblogs.com/Mychael/p/9034659.html