題目1004：Median

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題目描述：

    Given an increasing sequence S of N integers, the median is the number at the middle position. For example, the median of S1={11, 12, 13, 14} is 12, and the median of S2={9, 10, 15, 16, 17} is 15. The median of two sequences is defined to be the median of the non-decreasing sequence which contains all the elements of both sequences. For example, the median of S1 and S2 is 13.
    Given two increasing sequences of integers, you are asked to find their median.

輸入：

    Each input file may contain more than one test case.
    Each case occupies 2 lines, each gives the information of a sequence. For each sequence, the first positive integer N (≤1000000) is the size of that sequence. Then N integers follow, separated by a space.
    It is guaranteed that all the integers are in the range of long int.

輸出：

    For each test case you should output the median of the two given sequences in a line.

範例輸入：

4 11 12 13 145 9 10 15 16 17

範例輸出：

13

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思路：

• 用一維數組來儲存資料。由於該數組很大，應該考慮用儘可能少的數組來實現以減少記憶體消耗。並且，該數組只能作為全域變數，不能再main函數定義
• scanf函數讀取資料，只有按下斷行符號時資料才會從記憶體到所要讀取資料的變數。對於這段程式：

    while(scanf("%d",&s[0])!=EOF)   {        for(i=1;i<=s[0];i++)            scanf("%d",&s[i]);

　　　　　　}

　　　　輸入一串資料時，按下斷行符號之後，首先讀s[0],for迴圈就有了結束條件了～

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 1 #include<stdio.h> 2 #define N 1000001 3 long s[2000002]; 4 int main(int argc, char const *argv[]) 5 { 6     int i,j,t; 7     long m,n; 8     while(scanf("%d",&s[0])!=EOF) 9     {10         m=s[0];11         for(i=1;i<=m;i++)12             scanf("%d",&s[i]);13         if(scanf("%d",&s[m+1])==EOF)14             break;15         n=s[m+1];16         for(i=m+2;i<=n+m+1;i++)17             scanf("%d",&s[i]);18         s[0]=m+n;19         for(i=m+1;i<m+n+1;i++)20             s[i]=s[i+1];21         for(i=1;i<m+n;i++)22             for(j=i+1;j<=m+n;j++)    23                 if(s[i]>s[j])24                 {25                     t=s[i];26                     s[i]=s[j];27                     s[j]=t;28                 }29         t=(s[0]+1)/2;30         printf("%ld\n",s[t]);31     }32     return 0;33 }