HDU4525+公式

一开始TLE了。。。

 /*
 模拟
 */
 #include<stdio.h>
 #include<math.h>
 const int maxn = ;
 typedef __int64 int64;
 int64 a[ maxn ];
 int main(){
     int64 k;
     int n,k1,k2 ;
     int T;
     scanf("%d",&T);
     int ca = ;
     while( T-- ){
         scanf("%d%d%d%I64d",&n,&k1,&k2,&k);
         int64 sum = ;
         for( int i=;i<n;i++ ){
             scanf("%I64d",&a[ i ]);
             sum += a[ i ];
         }
         int64 cnt = ;
         int flag = -;
         while(  ){
             if( sum>k ) {
                 flag = ;
                 break;
             }//ok
             if( abs(k1+k2)<= ){
                 flag = -;
                 break;
             }
             int64 temp = a[  ];
             sum = ;
             for( int i=;i<n-;i++ ){
                 a[ i ] = k1*a[ i ]+k2*a[ i+ ];
                 sum += a[i];
             }
             a[ n- ] = k1*a[ n- ]+k2*temp;
             sum += a[ n- ];
             cnt++;
         }
         printf("Case #%d: ",ca++);
         if( flag== ) printf("%I64d\n",cnt);
         else printf("inf\n");
     }
     return ;
 }

后来推出公式

sigma(Ai)*(K1+K2)^t,t表示天数

 /*
 模拟
 */
 #include<stdio.h>
 #include<math.h>
 const int maxn = ;
 typedef __int64 int64;
 int main(){
     int ca = ;
     int T;
     scanf("%d",&T);
     while( T-- ){
         printf("Case #%d: ",ca++);
         int n,k1,k2;
         int64 k;
         scanf("%d%d%d%I64d",&n,&k1,&k2,&k);
         int64 sum = ;
         int temp;
         for( int i=;i<n;i++ ){
             scanf("%d",&temp);
             sum += temp;
         }
         if( sum>k ){
             printf("0\n");
             continue;
         }
         if( abs(k1+k2)<= ){
             printf("inf\n");
             continue;
         }
         double ans1 = sum*1.0/100000.0;
         double ans2 = (k)*1.0/100000.0;
         int cnt = ;
         while( ans1<=ans2 ){
             cnt++;
             ans1 = ans1*(k1+k2);
         }
         printf("%d\n",cnt);
     }
     return ;
 }