POJ 1698 —— Alice's Chance

#include<cstdio>
#include<cstring>
#include<string>
#include<queue>
#include<vector>
#include<algorithm>
#define inf 0x3f3f3f3f
using namespace std;
const int maxn = 50000;
int num_nodes;

struct Edge
{
int from, to, flow, cap;
}edge[maxn*2];

vector<int>G[maxn];
int edgenum;
void add(int u, int v, int c)
{
edge[edgenum].from = u;
edge[edgenum].to = v;
edge[edgenum].flow = 0;
edge[edgenum].cap = c;
edgenum++;

edge[edgenum].from = v;
edge[edgenum].to = u;
edge[edgenum].flow = 0;
edge[edgenum].cap = 0;
edgenum++;

G[u].push_back(edgenum-2);
G[v].push_back(edgenum-1);
}

int deep[maxn];
bool vis[maxn];
void BFS(int s, int t)
{
queue<int>Q;
memset(vis, false, sizeof vis);
Q.push(t);
vis[t] = true;
deep[t] = 0;
while(!Q.empty())
{
int now = Q.front();
Q.pop();
for(int i = 0;i<(int)G[now].size();i++)
{
int v = edge[G[now][i]].to;
if(!vis[v])
{
deep[v] = deep[now] + 1;
vis[v] = true;
Q.push(v);
}
}
}
}

int gap[maxn], front[maxn], cur[maxn];
int Augment(int s, int t)
{
int minflow = inf;
int begin = t;
while(begin != s)
{
Edge& e = edge[front[begin]];
minflow = min(minflow, e.cap - e.flow);
begin = e.from;
}

begin = t;
while(begin != s)
{
edge[front[begin]].flow += minflow;
edge[front[begin]^1].flow -= minflow;
begin = edge[front[begin]].from;
}
return minflow;
}

int Maxflow(int s, int t)
{
int flow = 0;
BFS(s, t);
memset(gap, 0, sizeof gap);
memset(cur, 0, sizeof cur);
for(int i = 0;i<num_nodes;i++)
gap[deep[i]]++;
int begin = s;
while(deep[s] < num_nodes)
{
if(begin == t)
{
flow += Augment(s, t);
begin = s;
}
bool flag = false;
for(int i = cur[begin];i<(int)G[begin].size();i++)
{
Edge& e = edge[G[begin][i]];
if(e.cap > e.flow && deep[begin] == deep[e.to] + 1)
{
front[e.to] = G[begin][i];
cur[begin] = i;
flag = true;
begin = e.to;
break;
}
}
if(!flag)
{
int k = num_nodes-1;
for(int i = 0;i<(int)G[begin].size();i++)
{
Edge& e = edge[G[begin][i]];
if(e.cap > e.flow)
k = min(k, deep[e.to]);
}
if(--gap[deep[begin]] == 0)	break;
gap[deep[begin] = k+1]++;
cur[begin] = 0;
if(begin != s)
{
begin = edge[front[begin]].from;
}
}
}
return flow;
}

void init()
{
for(int i = 0;i<num_nodes;i++)	G[i].clear();
edgenum = 0;
memset(deep, 0, sizeof deep);
}

vector<int>vec[10];
void Pre_time()
{
for(int i = 1;i<=7;i++)	vec[i].clear();
for(int i = 1;i<=7;i++)
{
int k = i;
while(k <= 350)
{
vec[i].push_back(k);
k += 7;
}
}
}

int a[25][25], d[25], w[25];
int main()
{
Pre_time();
int cas, n;
scanf("%d", &cas);
while(cas--)
{
scanf("%d", &n);
init();
int s = 0, t = 350+n+1;
int sum = 0;
for(int i = 1;i<=350;i++)
add(i, t, 1);
for(int i = 1;i<=n;i++)
{
scanf("%d%d%d%d%d%d%d%d%d", &a[i][1], &a[i][2], &a[i][3], &a[i][4], &a[i][5], &a[i][6], &a[i][7], &d[i], &w[i]);
sum += d[i];
}
for(int i = 1;i<=n;i++)
{
for(int j = 1;j<=7;j++)
{
if(a[i][j])
{
for(int t = 0;t<(int)vec[j].size();t++)
{
int u = vec[j][t];
if(u <= w[i]*7)
add(i+350, u, 1);
}
}
}
}
for(int i = 1;i<=n;i++)
add(s, 350+i, d[i]);
num_nodes = t+1;
int flow = Maxflow(s, t);
if(sum == flow)
printf("Yes\n");
else
printf("No\n");
}
return 0;
}