数字梯形问题

# include <bits/stdc++.h>
# define RG register
# define IL inline
# define Fill(a, b) memset(a, b, sizeof(a))
using namespace std;
typedef long long ll;
const int _(1010), __(1e6 + 10), INF(2e9);

IL ll Read(){
char c = '%'; ll x = 0, z = 1;
for(; c > '9' || c < '0'; c = getchar()) if(c == '-') z = -1;
for(; c >= '0' && c <= '9'; c = getchar()) x = x * 10 + c - '0';
return x * z;
}

int m, n, num, a[50][50], id[50][50];
int cnt, fst[_], w[__], to[__], nxt[__], dis[_], vis[_], S, T, cost[__], pe[_], pv[_], max_flow, max_cost;
queue <int> Q;

IL void Add(RG int u, RG int v, RG int f, RG int co){
cost[cnt] = co; w[cnt] = f; to[cnt] = v; nxt[cnt] = fst[u]; fst[u] = cnt++;
cost[cnt] = -co; w[cnt] = 0; to[cnt] = u; nxt[cnt] = fst[v]; fst[v] = cnt++;
}

IL bool Bfs(){
Q.push(S); Fill(dis, 127); dis[S] = 0; vis[S] = 1;
while(!Q.empty()){
RG int u = Q.front(); Q.pop();
for(RG int e = fst[u]; e != -1; e = nxt[e]){
if(!w[e] || dis[to[e]] <= dis[u] + cost[e]) continue;
dis[to[e]] = dis[u] + cost[e];
pe[to[e]] = e; pv[to[e]] = u;
if(!vis[to[e]]) vis[to[e]] = 1, Q.push(to[e]);
}
vis[u] = 0;
}
if(dis[T] >= dis[T + 1]) return 0;
RG int ret = INF;
for(RG int u = T; u != S; u = pv[u]) ret = min(ret, w[pe[u]]);
for(RG int u = T; u != S; u = pv[u]) w[pe[u]] -= ret, w[pe[u] ^ 1] += ret;
max_cost -= ret * dis[T]; max_flow += ret;
return 1;
}

IL void Calc(){  for(max_cost = 0; Bfs(); ); printf("%d\n", max_cost);  }

IL void Work1(){
Fill(fst, -
10b7a
1); cnt = 0; T = num + num + 1;
for(RG int i = 1; i <= n; ++i)
for(RG int j = 1; j < m + i; ++j)
Add(id[i][j], id[i][j] + num, 1, -a[i][j]);
for(RG int i = 1; i < n; ++i)
for(RG int j = 1; j < m + i; ++j)
Add(id[i][j] + num, id[i + 1][j], 1, 0), Add(id[i][j] + num, id[i + 1][j + 1], 1, 0);
for(RG int i = 1; i <= m; ++i) Add(S, id[1][i], 1, 0);
for(RG int i = 1; i < n + m; ++i) Add(id
[i] + num, T, 1, 0);
Calc();
}

IL void Work2(){
Fill(fst, -1); cnt = 0; T = num + num + 1;
for(RG int i = 1; i <= n; ++i)
for(RG int j = 1; j < m + i; ++j)
Add(id[i][j], id[i][j] + num, INF, -a[i][j]);
for(RG int i = 1; i < n; ++i)
for(RG int j = 1; j < m + i; ++j)
Add(id[i][j] + num, id[i + 1][j], 1, 0), Add(id[i][j] + num, id[i + 1][j + 1], 1, 0);
for(RG int i = 1; i <= m; ++i) Add(S, id[1][i], 1, 0);
for(RG int i = 1; i < n + m; ++i) Add(id
[i] + num, T, INF, 0);
Calc();
}

IL void Work3(){
Fill(fst, -1); cnt = 0; T = num + num + 1;
for(RG int i = 1; i <= n; ++i)
for(RG int j = 1; j < m + i; ++j)
Add(id[i][j], id[i][j] + num, INF, -a[i][j]);
for(RG int i = 1; i < n; ++i)
for(RG int j = 1; j < m + i; ++j)
Add(id[i][j] + num, id[i + 1][j], INF, 0), Add(id[i][j] + num, id[i + 1][j + 1], INF, 0);
for(RG int i = 1; i <= m; ++i) Add(S, id[1][i], 1, 0);
for(RG int i = 1; i < n + m; ++i) Add(id
[i] + num, T, INF, 0);
Calc();
}

int main(RG int argc, RG char *argv[]){
m = Read(); n = Read();
for(RG int i = 1; i <= n; ++i)
for(RG int j = 1; j < m + i; ++j)
a[i][j] = Read(), id[i][j] = ++num;
Work1(); Work2(); Work3();
return 0;
}