题面
Sol
显然是求这样一个东西
绿色的线为分割线,左上海拔为\(0\),右下为\(1\)
分隔线经过的边就是贡献的答案 那么这就是平面图最小割,转成对偶图求最短路就好了\(SPFA\)真心慢,以后还是跑\(Dijstra\)
# include# define RG register# define IL inline# define Fill(a, b) memset(a, b, sizeof(a))using namespace std;typedef long long ll;const int _(1e6 + 5);typedef int Arr[_];IL int Input(){ RG int x = 0, z = 1; RG char c = getchar(); for(; c < '0' || c > '9'; c = getchar()) z = c == '-' ? -1 : 1; for(; c >= '0' && c <= '9'; c = getchar()) x = (x << 1) + (x << 3) + (c ^ 48); return x * z;}int n, cnt, S, T, id[505][505], num;Arr dis, vis, first;struct Edge{ int to, next, w;} edge[_ << 1];queue Q;IL void Add(RG int u, RG int v, RG int w){ edge[cnt] = (Edge){v, first[u], w}, first[u] = cnt++;}IL int SPFA(){ Fill(dis, 127); dis[S] = 0; vis[S] = 1; Q.push(S); while(!Q.empty()){ RG int u = Q.front(); Q.pop(); for(RG int e = first[u]; e != -1; e = edge[e].next){ RG int w = edge[e].w, v = edge[e].to; if(dis[u] + w < dis[v]){ dis[v] = dis[u] + w; if(!vis[v]) vis[v] = 1, Q.push(v); } } vis[u] = 0; } return dis[T];}int main(RG int argc, RG char* argv[]){ Fill(first, -1), n = Input(); for(RG int i = 1; i <= n; ++i) for(RG int j = 1; j <= n; ++j) id[i][j] = ++num; T = num + 1; RG int r = n + 1; for(RG int i = 1; i <= r; ++i) for(RG int j = 1; j <= n; ++j){ RG int v = Input(); if(i == 1) Add(id[i][j], T, v); else if(i == r) Add(S, id[i - 1][j], v); else Add(id[i][j], id[i - 1][j], v); } for(RG int i = 1; i <= n; ++i) for(RG int j = 1; j <= r; ++j){ RG int v = Input(); if(j == 1) Add(S, id[i][j], v); else if(j == r) Add(id[i][j - 1], T, v); else Add(id[i][j - 1], id[i][j], v); } for(RG int i = 1; i <= r; ++i) for(RG int j = 1; j <= n; ++j){ RG int v = Input(); if(i == 1) Add(T, id[i][j], v); else if(i == r) Add(id[i - 1][j], S, v); else Add(id[i - 1][j], id[i][j], v); } for(RG int i = 1; i <= n; ++i) for(RG int j = 1; j <= r; ++j){ RG int v = Input(); if(j == 1) Add(id[i][j], S, v); else if(j == r) Add(T, id[i][j - 1], v); else Add(id[i][j], id[i][j - 1], v); } printf("%d\n", SPFA()); return 0;}