#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
//int cal(LL b, LL g){
//    if(g==0) return 0;
//    bool h[10];
//    memset(h,0,sizeof(h));
//    LL bb=1;
//    while(bb<=g){
//        int t=cal(b,g-bb);
//        if(t<10) h[t]=1;
//        if(b==1) break;
//        bb*=b;
//    }
//    for(int x=0;x<10; x++)
//        if(!h[x]) return x;
//}
int main()
{
//    for(int x=1; x<=5; x++){
//        for(int y=1; y<=5; y++){
//            printf("%d %d %d\n", x,y,cal(x,y));
//        }
//    }freopen("powers.in","r",stdin);int T;scanf("%d", &T);while(T--){int n;scanf("%d", &n);int ans = 0;for(int i=0; i<n; i++){int b,g;scanf("%d%d",&b,&g);if(b&1) ans^=g&1;else{if(g%(b+1)<=b-1) ans^=(g%(b+1))&1;else ans^=2;}}if(ans) puts("1");else puts("2");}return 0;
}

#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
LL C[22][22];
int main()
{freopen("popcorn.in", "r", stdin);memset(C, 0, sizeof(C));for(int i=0; i<=20; i++){C[i][0]=1;for(int j=1; j<=i; j++){C[i][j] = C[i-1][j-1]+C[i-1][j];}}int T,n,m;scanf("%d", &T);while(T--){scanf("%d %d", &n,&m);printf("%lld\n", C[n][m]);}return 0;
}

#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5+2;
int dis[maxn];
bool f[maxn];
vector <int> G[maxn];
int main()
{freopen("jumping.in","r",stdin);int T,n;scanf("%d", &T);while(T--){scanf("%d", &n);for(int i=1; i<=n; i++) G[i].clear();for(int i=1; i<=n; i++){int x;scanf("%d", &x);if(i-x>=1){G[i-x].push_back(i);}if(i+x<=n){G[i+x].push_back(i);}}memset(dis, 0x3f, sizeof(dis));memset(f, 0, sizeof(f));dis[n] = 0;queue <int> q;q.push(n);f[n] = 1;while(q.size()){int u = q.front();q.pop();for(int v : G[u]){if(!f[v]){dis[v] = dis[u]+1;f[v] = 1;q.push(v);}}}for(int i=1; i<=n; i++){if(dis[i] > n) dis[i] = -1;printf("%d\n", dis[i]);}}return 0;
}

#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e6+5;
typedef long long LL;
struct node{int x,y,p;node(){}node(int x,int y,int p):x(x),y(y),p(p){}bool operator < (const node &rhs) const{return x<rhs.x;}
}a[maxn],b[maxn];
int C;
namespace BIT{int c[maxn];void init(){memset(c, 0, sizeof(c));}inline int lowbit(LL x){return x&-x;}void add(LL pos, int val){for(LL i=pos; i<maxn; i+=lowbit(i))c[i] = max(c[i], val);}void Clear(LL pos){for(LL i=pos; i<maxn; i+=lowbit(i))c[i] = 0;}int query(LL pos){pos = min(pos, (LL)maxn-1);int ret = 0;for(LL i = pos; i>0; i-=lowbit(i))ret = max(ret, c[i]);return ret;}
}
using namespace BIT;
vector <int> v1[maxn*2];
vector <int> v2[maxn*2];
int cal(vector <int> &v){int n = v.size();if(n == 0) return 0;for(int i=0; i<n; i++) b[i] = a[v[i]];sort(b, b+n);int ret = 0;for(int i=0; i<n; i++){LL pos = b[i].x - (LL)b[i].p*b[i].p - C + 1;int d = query(pos)+1;ret = max(ret, d);pos = b[i].x + (LL)b[i].p*b[i].p;add(pos, d);}for(int i=0; i<n; i++){LL pos = b[i].x + (LL)b[i].p*b[i].p;Clear(pos);}return ret;
}
int main()
{freopen("bishops.in","r",stdin);int T; scanf("%d", &T);while(T--){int n,m;scanf("%d %d %d", &n,&m,&C);init();for(int i=0; i<=n*2; i++){v1[i].clear();v2[i].clear();}for(int i=1; i<=m; i++){scanf("%d %d %d", &a[i].x, &a[i].y, &a[i].p);v1[a[i].x+a[i].y].push_back(i);v2[a[i].x-a[i].y+n].push_back(i);}int ans = 0;for(int i=0; i<=n*2; i++){ans = max(ans, cal(v1[i]));ans = max(ans, cal(v2[i]));}printf("%d\n", ans);}return 0;
}

第二类Stirling数 S(p,k)S(p,k)的一个组合学解释是：将p个物体划分成k个非空的不可辨别的（可以理解为盒子没有编号）集合的方法数。k!S(p,k)是把p个人分进k间有差别(如：被标有房号）的房间(无空房）的方法数。S(p,k)的递推公式是：S(p,k)=k*S(p-1,k)+S(p-1,k-1) ,1<= k<=p-1边界条件：S(p,p)=1 ,p>=0    S(p,0)=0 ,p>=1

#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
int dp[3005][3005];
const int mod = 1e9+7;int main()
{freopen("galactic.in", "r", stdin);dp[1][1] = 1;for(int i=2; i<=3000; i++){dp[i][i] = 1;for(int j=1; j<=i; j++){dp[i][j] = ((LL)j*dp[i-1][j]+dp[i-1][j-1])%mod;}}int T;scanf("%d", &T);while(T--){int n, k;scanf("%d %d", &n,&k);if(k > n){puts("0");}else{int ans = dp[n][k];for(int i=1; i<=k; i++)ans = (LL)ans*i%mod;ans %= mod;printf("%d\n", ans);}}return 0;
}

#include <bits/stdc++.h>
using namespace std;
int dp[12][12][12];
int val[12][12][12];int main()
{freopen("commandos.in", "r", stdin);int T, n;scanf("%d", &T);while(T--){memset(dp, 0, sizeof(dp));memset(val, 0, sizeof(val));scanf("%d", &n);for(int i=0; i<n; i++){int f,x,y,h;scanf("%d %d %d %d", &f,&x,&y,&h);val[f][x][y] += h;}for(int f=10; f>=1; f--){for(int x=1; x<=10; x++){for(int y=1; y<=10; y++){dp[f][x][y] = max(dp[f][x][y], dp[f+1][x][y]);dp[f][x][y] = max(dp[f][x][y], dp[f][x-1][y]);dp[f][x][y] = max(dp[f][x][y], dp[f][x][y-1]);dp[f][x][y] += val[f][x][y];}}}printf("%d\n", dp[1][10][10]);}return 0;
}

#include <bits/stdc++.h>
using namespace std;
const int maxn = 2e5+10;
typedef long long LL;
int n,m;
int x[maxn],y[maxn],r[maxn];
pair <double,int> a[maxn*3];int main()
{freopen("walk.in","r",stdin);int T;scanf("%d", &T);while(T--){scanf("%d %d", &n,&m);int cnt = 0;for(int i=1; i<=n; i++){scanf("%d %d %d", &x[i],&y[i],&r[i]);if(y[i]<0) y[i]=-y[i];if(y[i]+r[i]>m) continue;int d = m-r[i];double dx=sqrt(1.0*d*d-1.0*y[i]*y[i]);a[++cnt] = make_pair(x[i]-dx, -r[i]);a[++cnt] = make_pair(x[i]+dx, r[i]);}LL sum=0,ans=0;sort(a+1,a+cnt+1);for(int i=1; i<=cnt; i++){sum += -a[i].second;ans = max(ans, sum);}printf("%lld\n", ans);}return 0;
}

#include <bits/stdc++.h>
using namespace std;
const int maxn = 5e5+10;
typedef long long LL;
vector <pair<int,int> > G[maxn];
int x[maxn];
int dep[maxn];
int stk[maxn];
int ans[maxn];
void dfs(int u, int fa, int d){stk[d] = u;int L = -1, R = d;while(L < R){int mid = (L+R+1)/2;if(dep[stk[mid]]>=dep[u]-x[u]) R=mid-1;else L=mid;}if(L>=0) --ans[stk[L]];++ans[u];for(auto &p : G[u]){int v = p.first;if(v == fa) continue;dep[v] = dep[u] + p.second;dfs(v, u, d+1);ans[u] += ans[v];}
}int main()
{freopen("car.in", "r", stdin);int T,n;scanf("%d", &T);while(T--){scanf("%d", &n);for(int i=1; i<=n; i++){G[i].clear();scanf("%d", &x[i]);ans[i]=0;}for(int i=1; i<n; i++){int a,b,c;scanf("%d%d%d", &a,&b,&c);G[a].emplace_back(b,c);G[b].emplace_back(a,c);}dfs(1,0,0);for(int i=1; i<n; i++){printf("%d ", ans[i]-1);}printf("%d\n", ans[n]-1);}return 0;
}