~~qndmx~~
by Belarus @ 2020-02-04 10:51:23
@[光明正大](/user/121563) 可以借个楼吗，我的代码也在这个点RE了
by 雷神山速度 @ 2020-02-29 11:57:14
```cpp
#include <bits/stdc++.h>
using namespace std;
int read(){
int num = 0, x = 1;
char c = getchar();
while(c < '0' || c > '9'){
if(c == '-')
x = -x;
c = getchar();
}
while(c <= '9' && c >= '0'){
num = (num << 1) + (num << 3) + c - '0';
c = getchar();
}
return num * x;
}
const int INF = 0x3f3f3f3f;
const int MAX_V = 200010;
int level[MAX_V];
int iter[MAX_V];
int n, m, s, t, sum;
int g[110][110];
int det[4][2] = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};
struct edge{
int to, cap, rev;
edge(int _to, int _cap, int _rev):to(_to), cap(_cap), rev(_rev){}
};
vector<edge>G[MAX_V];
struct point{
int x, y;
};
int Transf(point x){
return (x.x - 1) * m + x.y;
}
void add_edge(int from, int to, int cap){
G[from].push_back(edge(to, cap, G[to].size()));
G[to].push_back(edge(from, 0, G[from].size() - 1));
}
inline void bfs(int s){
memset(level, -1, sizeof(level));
queue<int>que;
level[s] = 0;
que.push(s);
while(!que.empty()){
int v = que.front();
que.pop();
for(register int i = 0; i < G[v].size(); ++i){
edge &e = G[v][i];
if(e.cap > 0 && level[e.to] < 0){
level[e.to] = level[v] + 1;
que.push(e.to);
}
}
}
return;
}
inline int dfs(int v, int t, int f){
if(v == t)
return f;
for(register int &i = iter[v]; i < G[v].size(); ++i){
edge &e = G[v][i];
if(e.cap > 0 && level[v] < level[e.to]){
int d = dfs(e.to, t, min(f, e.cap));
if(d > 0){
e.cap -= d;
G[e.to][e.rev].cap += d;
return d;
}
}
}
return 0;
}
int max_flow(int s, int t){
int flow = 0;
for(;;){
bfs(s);
if(level[t] < 0)
return flow;
memset(iter, 0, sizeof(iter));
int f;
while((f = dfs(s, t, INF)) > 0)
flow += f;
}
return flow;
}
int main(){
n = read(), m = read();
s = 0, t = n * m + 1, sum = 0;
for(register int i = 1; i <= n; ++i){
for(register int j = 1; j <= m; ++j){
g[i][j] = read();
sum += g[i][j];
}
}
for(register int i = 1; i <= n; ++i){
for(register int j = 1; j <= m; ++j){
point u = (point){i, j};
if((i + j) & 1){
for(register int k = 0; k < 4; ++k){
point v = u;
v.x += det[k][0];
v.y += det[k][1];
if(v.x >= 0 && v.x <= n && v.y >= 1 && v.y <= m){
add_edge(Transf(u), Transf(v), INF);
add_edge(Transf(v), Transf(u), 0);
}
}
add_edge(s, Transf(u), g[i][j]);
add_edge(Transf(u), s, 0);
}
else{
add_edge(Transf(u), t, g[i][j]);
add_edge(t, Transf(u), 0);
}
}
}
printf("%d\n", sum - max_flow(s, t));
return 0;
}
```
by 雷神山速度 @ 2020-02-29 11:57:54
@[雷神山速度](/user/320102)
话说我是WA不是RE...
不过我已经过了
by 光明正大 @ 2020-02-29 13:51:05
@[光明正大](/user/121563) 不重要了，帮帮忙~~我实在是太弱了~~
by 雷神山速度 @ 2020-02-29 20:44:19
@[雷神山速度](/user/320102)
你看你连边得地方写的是：
if(v.x>=0&&....)
应该是v.x>=1
by 光明正大 @ 2020-03-01 07:41:40
@[光明正大](/user/121563) 多谢
by 雷神山速度 @ 2020-03-02 20:07:39