[ACdream 1211 Reactor Cooling]无源无汇有上下界的可行流

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#pragma comment(linker, "/STACK:10240000")
#include <map>
#include <set>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <vector>
#include <cstdio>
#include <string>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <algorithm>

using namespace std;

#define X                   first
#define Y                   second
#define pb                  push_back
#define mp                  make_pair
#define all(a)              (a).begin(), (a).end()
#define fillchar(a, x)      memset(a, x, sizeof(a))
#define fillarray(a, b)     memcpy(a, b, sizeof(a))

typedef long long ll;
typedef pair<int, int> pii;
typedef unsigned long long ull;

#ifndef ONLINE_JUDGE
namespace Debug {
void RI(vector<int>&a,int n){a.resize(n);for(int i=0;i<n;i++)scanf("%d",&a[i]);}
void RI(){}void RI(int&X){scanf("%d",&X);}template<typename...R>
void RI(int&f,R&...r){RI(f);RI(r...);}void RI(int*p,int*q){int d=p<q?1:-1;
while(p!=q){scanf("%d",p);p+=d;}}void print(){cout<<endl;}template<typename T>
void print(const T t){cout<<t<<endl;}template<typename F,typename...R>
void print(const F f,const R...r){cout<<f<<", ";print(r...);}template<typename T>
void print(T*p, T*q){int d=p<q?1:-1;while(p!=q){cout<<*p<<", ";p+=d;}cout<<endl;}
}
#endif // ONLINE_JUDGE

template<typename T>bool umax(T&a, const T&b){return b<=a?false:(a=b,true);}
template<typename T>bool umin(T&a, const T&b){return b>=a?false:(a=b,true);}

const double PI = acos(-1.0);
const int INF = 0x3f3f3f3f;
const double EPS = 1e-14;

/* -------------------------------------------------------------------------------- */

const int maxn = 2e2 + 7;

struct Dinic {
private:
//const static int maxn = 1e3 + 7;
struct Edge {
int from, to, cap, least;
Edge(int u, int v, int w, int l): from(u), to(v), cap(w), least(l) {}
};
int s, t;
vector<Edge> edges;
vector<int> G[maxn];
bool vis[maxn];
int d[maxn], cur[maxn];

bool bfs() {
memset(vis, 0, sizeof(vis));
queue<int> Q;
Q.push(s);
d[s] = 0;
vis[s] = true;
while (!Q.empty()) {
int x = Q.front(); Q.pop();
for (int i = 0; i < G[x].size(); i ++) {
Edge &e = edges[G[x][i]];
if (!vis[e.to] && e.cap) {
vis[e.to] = true;
d[e.to] = d[x] + 1;
Q.push(e.to);
}
}
}
return vis[t];
}
int dfs(int x, int a) {
if (x == t || a == 0) return a;
int flow = 0, f;
for (int &i = cur[x]; i < G[x].size(); i ++) {
Edge &e = edges[G[x][i]];
if (d[x] + 1 == d[e.to] && (f = dfs(e.to, min(a, e.cap))) > 0) {
e.cap -= f;
edges[G[x][i] ^ 1].cap += f;
flow += f;
a -= f;
if (a == 0) break;
}
}
return flow;
}

public:
void clear() {
for (int i = 0; i < maxn; i ++) G[i].clear();
edges.clear();
memset(d, 0, sizeof(d));
}
void add(int from, int to, int cap, int least) {
edges.push_back(Edge(from, to, cap, least));
edges.push_back(Edge(to, from, 0, least));
int m = edges.size();
G[from].push_back(m - 2);
G[to].push_back(m - 1);
}

int solve(int s, int t) {
this->s = s; this->t = t;
int flow = 0;
while (bfs()) {
memset(cur, 0, sizeof(cur));
flow += dfs(s, 1e9);
}
return flow;
}

void out(int m) {
for (int i = 0; i < m; i ++) {
printf("%d\n", edges[i << 1].least + edges[i << 1 | 1].cap);
}
}
};
Dinic solver;
int tob[maxn], fromb[maxn];

int main() {
#ifndef ONLINE_JUDGE
freopen("in.txt", "r", stdin);
//freopen("out.txt", "w", stdout);
#endif // ONLINE_JUDGE
int n, m;
while (cin >> n >> m) {
solver.clear();
fillchar(tob, 0);
fillchar(fromb, 0);
for (int i = 0; i < m; i ++) {
int u, v, b, c;
scanf("%d%d%d%d", &u, &v, &b, &c);
solver.add(u, v, c - b, b);
tob[v] += b;
fromb[u] += b;
}
int total = 0;
for (int i = 1; i <= n; i ++) {
int dif = tob[i] - fromb[i];
if (dif > 0) solver.add(0, i, dif, 0);
if (dif < 0) solver.add(i, n + 1, - dif, 0);
total += abs(dif);
}
if (solver.solve(0, n + 1) != total / 2) puts("NO");
else {
puts("YES");
solver.out(m);
}
}
return 0;
}