Submission #364124

#	Time	Username	Problem	Language	Result	Execution time	Memory
364124		mosiashvililuka	Cat (info1cup19_cat)	C++14	77.50 / 100	672 ms	17900 KiB

cat

#include<bits/stdc++.h>
using namespace std;
int a,b,c,d,e,i,j,ii,jj,zx,xc,t,tes,f[200009],boo,pi,k[200009],qi,qqi,bo[200009],sup;
pair <int, int> p[3000009],q[200009],qq[200009];
void sw(int q, int w){
	swap(f[q],f[w]);
	swap(f[a-q+1],f[a-w+1]);
}
void dfs(int q){
	//zx++;
	bo[q]=t;
	if(f[q]<=a/2){
		if(bo[f[q]]==t) return;
		dfs(f[q]);
	}else{
		zx++;
		if(bo[a+1-f[q]]==t) return;
		dfs(a+1-f[q]);
	}
}
int main(){
	//ios_base::sync_with_stdio(false),cin.tie(0),cout.tie(0);
	//cin>>tes;
	scanf("%d\n",&tes);
	for(t=1; t<=tes; t++){
		//cin>>a;
		if(t!=tes) scanf("%d\n",&a); else scanf("%d",&a);
		for(i=1; i<=a; i++){
			//cin>>f[i];
			if(i==a) scanf("%d",&f[i]); else scanf("%d ",&f[i]);
		}
		boo=0;
		for(i=1; i<=a/2; i++){
			if(f[i]>a/2){
				boo=1;
				break;
			}
		}
		if(boo==0){
			/*boo=0;
			for(i=1; i<=a/2; i++){
				if(f[a-i+1]-f[i]!=a/2){
					boo=1;
					break;
				}
			}
			if(boo==1){
				cout<<-1<<endl;
				continue;
			}*/
			pi=0;
			for(i=1; i<=a/2; i++){
				k[f[i]]=i;
			}
			for(i=1; i<=a/2; i++){
				if(k[i]==i) continue;
				pi++;
				p[pi].first=k[i];
				p[pi].second=i;
				c=k[i];d=i;
				swap(k[i],k[f[i]]);
				swap(f[c],f[d]);
			}
			for(i=1; i<=pi; i++){
				swap(f[a-p[i].first+1],f[a-p[i].second+1]);
			}
			boo=0;
			for(i=2; i<=a; i++){
				if(f[i]<f[i-1]){
					boo=1;
					break;
				}
			}
			if(boo==1){
//				cout<<-1<<endl;
				printf("-1\n");
				continue;
			}
			//cout<<pi<<" "<<pi<<endl;
			printf("%d %d\n",pi,pi);
			for(i=1; i<=pi; i++){
				//cout<<p[i].first<<" "<<p[i].second<<endl;
				printf("%d %d\n",p[i].first,p[i].second);
			}
			continue;
		}
		boo=0;
		for(i=1; i<=a/2; i++){
			j=a-i+1;
			if(f[i]+f[j]!=a+1){
				boo=1;
				break;
			}
		}
		if(boo==0){
			//printf("%d 0\n",a);
		}else{
			printf("-1\n");
			continue;
		}
		qi=0;qqi=0;
		for(i=1; i<=a/2; i++){
			if(f[i]>f[a-i+1]){
				qi++;
				q[qi].first=i;
				q[qi].second=a-i+1;
			}else{
				/*qqi++;
				qq[qqi].first=a-i+1;
				qq[qqi].second=i;*/
			}
		}
		if(qi%2==1){
			printf("-1\n");
			continue;
		}else{
			//printf("%d 0\n",a);
		}
		c=0;d=0;e=0;
		for(i=1; i<=a/2; i++){
			if(bo[i]==t) continue;
			e++;
			zx=0;
			dfs(i);
			c+=zx/2;
			d+=zx%2;
		}
		sup=a/2-(e+c-d/2)+qi/2;
		//printf("%d 0\n",a/2-(e+c-d/2)+qi/2);
		pi=0;
		for(i=1; i+1<=qi; i+=2){
			pi++;
			p[pi].first=q[i].second;p[pi].second=q[i+1].first;
			sw(q[i].second,q[i+1].first);
		}
		//sample
		for(i=1; i<=a/2; i++){
			k[f[i]]=i;
		}
		for(i=1; i<=a/2; i++){
			if(k[i]==i) continue;
			pi++;
			p[pi].first=k[i];
			p[pi].second=i;
			c=k[i];d=i;
			swap(k[i],k[f[i]]);
			swap(f[c],f[d]);
		}
		printf("%d %d\n",sup,pi);
		for(i=1; i<=pi; i++){
			//cout<<p[i].first<<" "<<p[i].second<<endl;
			printf("%d %d\n",p[i].first,p[i].second);
		}
	}
	return 0;
}

Compilation message (stderr)

cat.cpp: In function 'int main()':
cat.cpp:24:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   24 |  scanf("%d\n",&tes);
      |  ~~~~~^~~~~~~~~~~~~
cat.cpp:27:19: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   27 |   if(t!=tes) scanf("%d\n",&a); else scanf("%d",&a);
      |              ~~~~~^~~~~~~~~~~
cat.cpp:27:42: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   27 |   if(t!=tes) scanf("%d\n",&a); else scanf("%d",&a);
      |                                     ~~~~~^~~~~~~~~
cat.cpp:30:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   30 |    if(i==a) scanf("%d",&f[i]); else scanf("%d ",&f[i]);
      |             ~~~~~^~~~~~~~~~~~
cat.cpp:30:42: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   30 |    if(i==a) scanf("%d",&f[i]); else scanf("%d ",&f[i]);
      |                                     ~~~~~^~~~~~~~~~~~~

• Subtask 1: 10.5 / 15
• Subtask 2: 10 / 10
• Subtask 3: 17.5 / 25
• Subtask 4: 15 / 15
• Subtask 5: 24.5 / 35