Is Bigger Smarter?

code

6 年前

Is Bigger Smarter?

时间： 1ms 内存：64M

描述：

Some people think that the bigger an elephant is, the smarter it is. To disprove this, you want to analyze a collection of elephants and place as large a subset of elephants as possible into a sequence whose weights are increasing but IQ's are decreasing.

输入：

The input will consist of data for a bunch of elephants, at one elephant per line terminated by the end-of-file. The data for each particular elephant will consist of a pair of integers: the first representing its size in kilograms and the second representing its IQ in hundredths of IQ points. Both integers are between 1 and 10,000. The data contains information on at most 1,000 elephants. Two elephants may have the same weight, the same IQ, or even the same weight and IQ.

输出：

The first output line should contain an integer n, the length of elephant sequence found. The remaining n lines should each contain a single positive integer representing an elephant. Denote the numbers on the ith data line as W[i] and S[i]. If these sequence of n elephants are a[1], a[2],..., a[n] then it must be the case that W[a[1]] < W[a[2]] < ... < W[a[n]] and S[a[1]] > S[a[2]] > ... > S[a[n]] In order for the answer to be correct, n must be as large as possible. All inequalities are strict: weights must be strictly increasing, and IQs must be strictly decreasing. Your program can report any correct answer for a given input.

示例输入：

示例输出：

提示：

参考答案（内存最优[776]）：

#include<stdio.h>
#define N 1005
FILE *f1,*f2;
typedef struct node
{
        long w,s,num;
}node;
node a[N];
long f[N],b[N],q[N],n;

int bigger(node x,node y)
{
     if (x.w!=y.w) return (x.w>y.w);
     else return (x.s<y.s);
}

void sort(long left,long right)
{
     long i,j;
     node x,t;
     i=left;j=right;
     x=a[(i+j)/2];
     while (i<=j)
     {
           while (bigger(x,a[i])) i++;
           while (bigger(a[j],x)) j--;
           if (i<=j)
           {     t=a[i];a[i]=a[j];a[j]=t;
                 i++;j--;
           }
     }
     if (left<j) sort(left,j);
     if (i<right) sort(i,right);
}
int main()
{
    long i,j,k,max;
    i=1;
    while (scanf("%ld%ld",&a[i].w,&a[i].s)==2)  a[i].num=i++;  
    n=i-1;
    sort(1,n);
    for (i=1;i<=n;i++) {f[i]=1;b[i]=i;}
    for (i=1;i<=n;i++)
        for (j=1;j<i;j++)
            if (a[j].w<a[i].w&&a[j].s>a[i].s&&f[j]+1>f[i])
            {  f[i]=f[j]+1; b[i]=j; }
    max=0;
    for (i=1;i<=n;i++)
        if (f[i]>max) {max=f[i];k=i;}
    printf("%ld\n",max);
    q[1]=a[k].num; i=1;
    while (b[k]!=k) {q[++i]=a[b[k]].num; k=b[k];}
    for (i=max;i>=1;i--)
        printf("%ld\n",q[i]);
    return 0;
}

参考答案（时间最优[0]）：

#include<stdio.h> 
#define N 1005 
FILE *f1,*f2; 
typedef struct node 
{ 
        long w,s,num; 
}node; 
node a[N]; 
long f[N],b[N],q[N],n; 
  
int bigger(node x,node y) 
{ 
     if (x.w!=y.w) return (x.w>y.w); 
     else return (x.s<y.s); 
} 
  
void sort(long left,long right) 
{ 
     long i,j; 
     node x,t; 
     i=left;j=right; 
     x=a[(i+j)/2]; 
     while (i<=j) 
     { 
           while (bigger(x,a[i])) i++; 
           while (bigger(a[j],x)) j--; 
           if (i<=j) 
           {     t=a[i];a[i]=a[j];a[j]=t; 
                 i++;j--; 
           } 
     } 
     if (left<j) sort(left,j); 
     if (i<right) sort(i,right); 
} 
int main() 
{ 
    long i,j,k,max; 
    i=1; 
    while (scanf("%ld%ld",&a[i].w,&a[i].s)==2)  a[i].num=i++;   
    n=i-1; 
    sort(1,n); 
    for (i=1;i<=n;i++) {f[i]=1;b[i]=i;} 
    for (i=1;i<=n;i++) 
        for (j=1;j<i;j++) 
            if (a[j].w<a[i].w&&a[j].s>a[i].s&&f[j]+1>f[i]) 
            {  f[i]=f[j]+1; b[i]=j; } 
    max=0; 
    for (i=1;i<=n;i++) 
        if (f[i]>max) {max=f[i];k=i;} 
    printf("%ld\n",max); 
    q[1]=a[k].num; i=1; 
    while (b[k]!=k) {q[++i]=a[b[k]].num; k=b[k];} 
    for (i=max;i>=1;i--) 
        printf("%ld\n",q[i]); 
    return 0; 
}

题目和答案均来自于互联网，仅供参考，如有问题请联系管理员修改或删除。