https://codeforces.com/contest/1678

A.Tokitsukaze and All Zero Sequence 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 int n; int a[MAXN]; inline void work(signed CASE=1,bool FINAL_CASE=false) { n=read(); int zero=0; set s; for(int i=1;i<=n;i++) { int x=read(); zero+=(x==0); s.insert(x); } if(zero) { printf("%d\n",n-zero); return; } int k=n-sz(s); if(k==0) { printf("%d\n",n+1); } else { printf("%d\n",n); } return; } signed main() { // ios::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr); //freopen(".in", "r", stdin);//freopen(".out", "w", stdout); signed T=(signed)read();//scanf("%d",&T);//cin>>T; for(signed CASE=1; CASE<=T; CASE++) { // //printf("Case #%d: ",CASE); //printf("Case %d: ",CASE); //printf("Case #%d: \n",CASE); //printf("Case %d: \n",CASE); work(CASE,CASE==T); if(CASE!=T) {} } return 0; }

B1.Tokitsukaze and Good 01-String (easy version) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 int n,ans; bool flag; char lst=0; inline void work(signed CASE=1,bool FINAL_CASE=false) { n=read(); vector v; for(int i=1;i<=n;i++) { char c=nc(); if(c==lst) { v.back()++; } else { v.pb(1); lst=c; } } for(auto x:v) { if(x&1) { flag=!flag; } ans+=flag; } printf("%lld\n",ans); return; } signed main() { // ios::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr); //freopen(".in", "r", stdin);//freopen(".out", "w", stdout); signed T=(signed)read();//scanf("%d",&T);//cin>>T; for(signed CASE=1; CASE<=T; CASE++) { // //printf("Case #%d: ",CASE); //printf("Case %d: ",CASE); //printf("Case #%d: \n",CASE); //printf("Case %d: \n",CASE); work(CASE,CASE==T); if(CASE!=T) { ans=0; flag=false; lst=0; } } return 0; }

B2.Tokitsukaze and Good 01-String (hard version) 一开始没找出B2规律，然后被带飞 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 int n,ans,ls=-1,cnt; bool flag; char lst=0; inline void work(signed CASE=1,bool FINAL_CASE=false) { n=read(); vector v; for(int i=1;i<=n;i++) { char c=nc(); if(c==lst) { v.back()++; } else { v.pb(1); lst=c; } } for(auto &x:v) { if(x&1) { flag=!flag; x=(x==1)?0:x; } else if(flag) { x=(x==2)?0:x; } ans+=flag; } for(int i=0;i1?cnt:1); return; } signed main() { // ios::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr); //freopen(".in", "r", stdin);//freopen(".out", "w", stdout); signed T=(signed)read();//scanf("%d",&T);//cin>>T; for(signed CASE=1; CASE<=T; CASE++) { // //printf("Case #%d: ",CASE); //printf("Case %d: ",CASE); //printf("Case #%d: \n",CASE); //printf("Case %d: \n",CASE); work(CASE,CASE==T); if(CASE!=T) { lst=cnt=ans=0; flag=false; ls=-1; } } return 0; }

C.Tokitsukaze and Strange Inequality 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 int n,ans; int a[MAXN]; int f[5009][5009]; inline void work(signed CASE=1,bool FINAL_CASE=false) { n=read(); for(int i = 1; i <= n; i++) { a[i]=read(); } for(int i = 1; i <= n; i++) { f[i][n] = a[n] < a[i]; for(int j = n - 1; j >= i + 1; j--) { f[i][j] = f[i][j + 1] + (a[j] < a[i]); } } for(int i = 2; i <= n; i++) { for(int j = 1; j <= n; j++) { f[i][j] += f[i - 1][j]; } } for(int i=1;i<=n;i++) { for(int j=i+1;j<=n;j++) { if(a[j]>a[i]) { int l=i+1,r=j-1; if(l<=r && r>T; for(signed CASE=1; CASE<=T; CASE++) { // //printf("Case #%d: ",CASE); //printf("Case %d: ",CASE); //printf("Case #%d: \n",CASE); //printf("Case %d: \n",CASE); work(CASE,CASE==T); if(CASE!=T) { ans=0; } } return 0; }

Codeforces Round #789 (Div. 2)