数据结构课程笔记--（1）求最大子列的问题

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1.题目一

------------------------------------算法一：在线解决

#include<stdio.h>int max(int L[],int N);int main(){   int L[100000],N,i;   scanf("%d",&N);   for(i=0;i<N;i++)   scanf("%d",&L[i]);   printf("%d\n",max(L,N));   return 0;}int max(int L[],int N){int i,j,thissum,maxsum=0;for (i=0;i<N ;i++ ){thissum+=L[i];if (thissum>maxsum)maxsum = thissum;else if(thissum<0)thissum=0;}return maxsum;}

时间复杂度：T(N) = O(N)

-------------------------------算法二：两个循环

算法二：#include<stdio.h>int max(int L[],int N);int main(){   int L[100000],N,i;   scanf("%d",&N);   for(i=0;i<N;i++)   scanf("%d",&L[i]);   printf("%d\n",max(L,N));   return 0;}int max(int L[],int N){int thissum,maxsum=0;int i,j;for (i=0;i<N ;i++ ){thissum = 0;for (j=i;j<N ; j++){thissum += L[k];if(thissum > maxsum)maxsum = thissum;}}return maxsum;}

时间复杂度：T(N) = O(N^2)

2.题目2：不但求最大子列的和，还有最大子列的元素

#include<stdio.h>int max(int L[],int N);int main(){   int L[100000],N,i;   scanf("%d",&N);   for(i=0;i<N;i++)   scanf("%d",&L[i]);   max(L,N);   return 0;}int max(int L[],int N){int thissum,maxsum=0;int i,j,k=0;int left,right;for (i=0;i<N ;i++ ){thissum = 0;if(L[i] <= 0){            k++;}for (j=i;j<N ; j++){thissum += L[j];if(thissum > maxsum){maxsum = thissum;right = L[j];left = L[i];}}}if(k == N){        printf("%d %d %d\n",0,L[0],L[N-1]);}else{        printf("%d %d %d\n",maxsum,left,right);}}

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