Title Link: (bzoj) https://www.lydsy.com/JudgeOnline/problem.php?id=4386
(luogu) https://www.luogu.org/problemnew/show/P3597
Why can't I do this?
First of all, if all the edge weights are \ (1 \), a new counter will be created, with each point connected to the counter and the counter connected to the self loop. Then the adjacent matrix can be multiplied by a fast power
If the edge has \ (2 \) and \ (3 \), create a new node to connect to the outgoing point
There are many details, especially when judging whether it is greater than \ (k \), long long cannot be exploded (it is said that this data water, so I can't guarantee that the following code won't be stuck)
Code
#include<cstdio> #include<cstdlib> #include<cstring> #include<cassert> #include<iostream> #define llong long long using namespace std; inline int read() { int x=0; bool f=1; char c=getchar(); for(;!isdigit(c);c=getchar()) if(c=='-') f=0; for(; isdigit(c);c=getchar()) x=(x<<3)+(x<<1)+(c^'0'); if(f) return x; return -x; } const int N = 121; llong p; struct Matrix { llong a[N+3][N+3]; int n; Matrix() {} Matrix(int _n) {n = _n; for(int i=0; i<=n; i++) for(int j=0; j<=n; j++) a[i][j] = 0ll;} void init(int _n) {n = _n; for(int i=0; i<=n; i++) for(int j=0; j<=n; j++) a[i][j] = 0ll;} void unitize(int _n) {n = _n; a[0][0] = 0ll; for(int i=1; i<=n; i++) for(int j=1; j<=n; j++) a[i][j] = i==j?1ll:0ll;} void output() {if(a[0][0]==-1) puts("gg"); for(int i=1; i<=n; i++) {for(int j=1; j<=n; j++) printf("%d ",a[i][j]); puts("");}} Matrix operator *(const Matrix &arg) const { Matrix ret(n); for(int i=1; i<=n; i++) { for(int j=1; j<=n; j++) { for(int k=1; k<=n; k++) { if(k==n) { if(arg.a[j][k]>0 && (a[i][j]>=p/arg.a[j][k]+1 || ret.a[i][k]>=p-a[i][j]*arg.a[j][k])) { ret.a[0][0] = -1; return ret; } } ret.a[i][k] = ret.a[i][k]+a[i][j]*arg.a[j][k]; } } } llong sum = 0ll; for(int i=1; i<=n/3; i++) { if(sum>=p-ret.a[i][n]) {ret.a[0][0] = -1; return ret;} sum += ret.a[i][n]; } return ret; } } g,pw[65],tmp; int n,m; llong solve() { pw[0] = g; int i = 0; for(i=1; i<=61; i++) { pw[i] = pw[i-1]*pw[i-1]; if(pw[i].a[0][0]==-1) { break; } } if(i==62) {return -1;} llong ret = 0ll; g.unitize(n+n+n+1); for(i--; i>=0; i--) { tmp = g*pw[i]; if(tmp.a[0][0]!=-1) { ret|=(1ll<<i); g = tmp; } } return ret; } int main() { scanf("%d%d%lld",&n,&m,&p); p+=n; g.init(n+n+n+1); for(int i=1; i<=m; i++) { int x,y,w; scanf("%d%d%d",&x,&y,&w); if(w==1) {g.a[x][y]++;} else if(w==2) {g.a[x+n][y]++;} else if(w==3) {g.a[x+n+n][y]++;} } for(int i=1; i<=n; i++) { g.a[i][i+n]++; g.a[i+n][i+n+n]++; g.a[i][n+n+n+1]++; } g.a[n+n+n+1][n+n+n+1]++; llong ans = solve(); printf("%lld\n",ans); return 0; }