ds wk1

1.最大子列和输出（按在线算法）

#include<stdio.h>
#include<stdlib.h>

#define MAXNUM 100000
int main()
{
    int a[MAXNUM];
    int i, k;
    int thisnum, maxnum;
    thisnum = 0;
    maxnum = 0;
    scanf("%d", &k);
    for (i = 0; i < k; i++){
        scanf("%d", &a[i]);
    }
    
    for (i = 0; i < k;i++){
        thisnum += a[i];
        if(thisnum>maxnum)
            maxnum = thisnum;
        if(thisnum<0)
            thisnum = 0;
    }
    printf("%d", maxnum);
    //system("pause");
    return 0;
}

2.最大子列和 输出最大和，起始和末尾数字

#include<stdio.h>
#include<stdlib.h>

#define MAXNUM 100000
int main()
{
    int a[MAXNUM];
    int i, k;
    int thisnum, maxnum;
    int start, end, head, tail;

    thisnum = 0;
    maxnum = 0;
    start = 0;
    end = 0;
    head = 0;
    tail = 0;

    scanf("%d", &k);
    for (i = 0; i < k; i++){
        scanf("%d", &a[i]);
    }
    
    for (i = 0; i < k;i++){
        thisnum += a[i];
        if(thisnum>=0){
            end=i;
        }
        if(thisnum==maxnum&&maxnum==0){
            head = start;
            tail = end;
        }
        if(thisnum>maxnum){
            maxnum = thisnum;
            head = start;
            tail = end;
        }

        if(thisnum<0){
            thisnum = 0;
            start = i + 1;
            end = i + 1;
        }
        
            
    }
    if(head==tail&&a[head]<0){
        head = 0;
        tail = k - 1;
    }
    printf("%d %d %d", maxnum,a[head],a[tail]);
    //system("pause");
    return 0;
}

3.BinarySearch

#include <stdio.h>
#include <stdlib.h>

#define MAXSIZE 10
#define NotFound 0
typedef int ElementType;

typedef int Position;
typedef struct LNode *List;
struct LNode {
    ElementType Data[MAXSIZE];
    Position Last; /* 保存线性表中最后一个元素的位置 */
};

List ReadInput(); /* 裁判实现，细节不表。元素从下标1开始存储 */
Position BinarySearch( List L, ElementType X );

int main()
{
    List L;
    ElementType X;
    Position P;
    L = ReadInput();
    scanf("%d", &X);
    P = BinarySearch( L, X );
    printf("%d\n", P);

    return 0;
}

/* 你的代码将被嵌在这里 */

Position BinarySearch( List L, ElementType X )
{
    Position left = 1;
    Position right = L->Last;

    Position mid;

    while(left<=right)//如果区间不为空就继续查找
    {
        mid=left+(right-left)/2;//取查找区间正中元素的下标
        if(X==L->Data[mid])
            return mid;
        else if(X>L->Data[mid])
            left=mid+1;//设置新的查找区间的左端点
        else
            right=mid-1;//设置新的查找区间的右端点
    }
     return NotFound;

}