s1.cpp

#include <iostream> 
using namespace std;


int main(){

	int N;
	int a, b, c;
	cin>>N;

	for(int i=0; i<N; ++i){

		cin>>a>>b>>c;

		if(a==0 && b==0 && c==0){
			cout<<"Over 9000 solutions"<<endl;
			continue;
		}

		if(a==0 && b==0){
			cout<<"No solution"<<endl;
			continue;
		}

		if(a==0){
			cout<<"1 solution"<<endl;
			continue;
		}

		int dis = (b*b)-(4*a*c);

		if(dis<0){
			cout<<"No solution"<<endl;
			continue;
		}
			
		if(dis==0){
			cout<<"1 solution"<<endl;
			continue;
		}

		else{
			cout<<"2 solutions"<<endl;
			continue;
		}

	}
	return 0;
}

s2.cpp

#include <iostream>
#include <string>
using namespace std;
#define INF 200000000

int R, C, room[100][100], orgroom[100][100];
string tin;
bool fail;


void flood(int row, int c, int lastdir, int u, int d, int l, int r){
	
	if(fail==1) return;
	if(row<0 || c<0) return;
	if(row>R-1 || c>C-1) return;
	if(room[row][c]==-1) return;

	int dis = (int)u+(int)d+(int)l+(int)r;

	if(dis>=room[row][c]) return;
	if(dis<room[row][c]){
		room[row][c]=dis;
	}

	//up
	if(lastdir!=1){	
		flood(row-1,c,0,1,d,l,r);
	}
	//down
	if(lastdir!=0){
		flood(row+1,c,1,u,1,l,r);
	}
	//left
	if(lastdir!=3){
		flood(row,c-1,2,u,d,1,r);
	}
	//right
	if(lastdir!=2){
		flood(row,c+1,3,u,d,l,1);
	}

	return;

}


void copyorg(){
	for(int r=0; r<R; ++r){
		for(int c=0; c<C; ++c){
			room[r][c]=orgroom[r][c];
		}
	}
}

void clearorg(){
	for(int r=0; r<R; ++r){
		for(int c=0; c<C; ++c){
			orgroom[r][c]=0;
		}
	}
}

void print(int ar[100][100] ){

	for(int r=0; r<R; ++r){
		for(int c=0; c<C; ++c){
			if(ar[r][c]==INF)
				cout<<"I";
			else if(ar[r][c]==-1)
				cout<<"w";
			else
				cout<<ar[r][c];
		}cout<<endl;
	}cout<<endl;
}


int main(){

	int N;
	cin>>N;

	for(int n=0; n<N; ++n){
		
		cin>>R>>C;
		clearorg();
		fail=0;

		//input
		for(int r=0; r<R; ++r){
			cin>>tin;
			//cout<<tin<<endl;
			for(int c=0; c<C; ++c){	
				if(tin[c]=='.'){
					orgroom[r][c]=-1;
				}
				else{
					orgroom[r][c]=INF;
				}
			}
		}
		
		copyorg();
		for(int r=0; r<R; ++r){
			for(int c=0; c<C; ++c){
		
				
				if(room[r][c]==INF){
					copyorg();
					
					flood(r,c,-1,0,0,0,0); //0up,1down,2left,3right
				
//					print(room);
					
					for(int r1=0; r1<R; ++r1){
						for(int c1=0; c1<C; ++c1){
							if(room[r1][c1]>2){
								fail=1;
								goto fin;
							}
						}
					}
					copyorg();

				}

			}
		}

		fin:
		cout<<"Room "<<n+1<<": "<<(fail?"NO":"YES")<<endl;

	}

	return 0;
}

s3.cpp

#include <iostream>
using namespace std;


int S, N;
int W[150], V[150];
int K[151][151];




int main(){

	cin>>S>>N;

	for(int n=0; n<N; ++n){
		cin>>W[n]>>V[n];
	}

	for(int n=0; n<=N; ++n){
		for(int w=0; w<=S; ++w){
	
			if(n==0 || w==0){
				K[n][w]=0;
			}
			else K[n][w]=K[n-1][w];

			if( W[n-1]<=w && K[n][w-W[n-1]]+V[n-1] > K[n][w] ){
				K[n][w]=K[n][w-W[n-1]]+V[n-1];
			}


		}
	}
	
	/*for(int n=0; n<N; ++n){
		for(int w=0; w<=S; ++w){
		cout<<K[n][w];
	}	cout<<endl;}*/


	cout<<K[N-1][S]<<endl;

	return 0;
}

s4.cpp

#include <iostream>
#include <cmath>
using namespace std;

int total=0;
int N;


int main(){

	cin>>N;
	if(N==3){ cout<<0<<endl; return 0;}
	if(N==4){ cout<<1<<endl; return 0;}
	if(N==5){ cout<<5<<endl; return 0;}


	int nlines;
	total=1;
	int i;
	for(int n=5; n<=N; ++n){
		
		nlines = n-3;

		//total+=nlines;
		int toadd=n-3;
		for(i=1; i <= (nlines/2); ++i){
			total+=2*(toadd);
			toadd+=(nlines-1)-i;
			for(int o=0; o<i-1; ++o){
				toadd-=1;
			}
		}
		if(n%2==0){
			total+=(toadd);
		}

	}

	cout<<total<<endl;
	
	return 0;

}

s4broken.cpp

#include <iostream>
#include <cmath>
using namespace std;

int total=0;
int N;


int main(){

	cin>>N;
	if(N==3){ cout<<0<<endl; return 0;}
	if(N==4){ cout<<1<<endl; return 0;}
	if(N==5){ cout<<5<<endl; return 0;}


	int nlines;
	total=1;
	int i;
	for(int n=5; n<=N; ++n){
		
		nlines = n-3;

		//total+=nlines;
		int toadd=n-3;
		for(i=1; i <= (nlines/2); ++i){
			total+=2*(toadd);
			toadd+=nlines-1-i;
		}
		if(n%2==0){
			total+=(toadd);
		}

	}

	cout<<total<<endl;
	
	return 0;

}

s4improved.py

from math import factorial
N=int(input())
if(N<=3):
    print(0)
else:
    print( int((factorial(N)) / (factorial(4)*factorial(N-4))) )

s5.cpp

#include <iostream>
using namespace std;


bool blocked[400][400];
int up[400][400], lef[400][400];
int R, C, res=0;

void resultify(int r, int c){
	if(res < 2*r + 2*c ){
		res=2*r + 2*c;
	}
}

int main(){

	cin>>R>>C;
	string tin;
	for(int r=0; r<R; ++r){
		cin>>tin;
		for(int c=0; c<C; ++c){
			if(tin[c]=='X') blocked[r][c]=1;
			else blocked[r][c]=0;
		}
	}

	for(int r=0; r<R; ++r){
		for(int c=0; c<C; ++c){
			
			if(blocked[r][c])
				continue;	

			if(r==0){
				up[r][c]=1;
			}
			else{
				up[r][c]=up[r-1][c]+1;
			}

			if(c==0){
				lef[r][c]=1;
			}
			else{
				lef[r][c]=lef[r][c-1]+1;
			}

		}
	}

	
	int t;

	for(int r=0; r<R; ++r){
		for(int c=0; c<C; ++c){

			t=lef[r][c];
			for(int r1=0; r1<up[r][c]; ++r1){
				t=min(lef[r-r1][c],t);
				resultify(r1+1,t);
			}

		}
	}

	cout<<res-1<<endl;
	return 0;
}

s5broken.cpp

#include <iostream>
using namespace std;


bool blocked[400][400];
int up[400][400], lef[400][400];
int R, C;


int main(){

	cin>>R>>C;
	string tin;
	for(int r=0; r<R; ++r){
		cin>>tin;
		for(int c=0; c<C; ++c){
			if(tin[c]=='X') blocked[r][c]=1;
			else blocked[r][c]=0;
		}
	}

	for(int r=0; r<R; ++r){
		for(int c=0; c<C; ++c){
			
			if(blocked[r][c])
				continue;	

			if(r==0){
				up[r][c]=1;
			}
			else{
				up[r][c]=up[r-1][c]+1;
			}

			if(c==0){
				lef[r][c]=1;
			}
			else{
				lef[r][c]=lef[r][c-1]+1;
			}

		}
	}

	
	int res=0;

	for(int r=0; r<R; ++r){
		for(int c=0; c<C; ++c){

			if(res < 2*up[r][c] + 2*lef[r][c] ){
				res=2*up[r][c] + 2*lef[r][c];
			}

		}
	}

	cout<<res-1<<endl;
	return 0;
}