0-1背包问题

来源：互联网发布：日语翻译哪个软件好编辑：程序博客网时间：2024/06/12 23:37
//递归#include<stdio.h>#define n 5int w[n] = {2,2,6,5,4};//表示每个物品的重量 int v[n] = {6,3,5,4,6};//每个物品的价值 int m(int i,int j){int a,b;if(i == n - 1){if(j >= w[i])return v[i];elsereturn 0;}if(j < w[i])return m(i + 1,j);a = m(i + 1,j - w[i]) + v[i];b = m(i + 1,j);return a > b ? a : b;}int main(){int c = 10;printf("%d.",m(0,c));return 0; }==========================================================//备忘录#include<stdio.h>#define n 5#define c 10int w[n] = {2,2,6,5,4};//表示每个物品的重量 int v[n] = {6,3,5,4,6};//每个物品的价值int s[n][c + 1];int m(int i,int j){int a,b;int result;if(s[i][j] >= 0)return s[i][j];if(i == n - 1){if(j < w[i])result = 0;elseresult = v[i];}else if(j < w[i]){result = m(i + 1,j);}else{a = m(i + 1,j);b = m(i + 1,j - w[i]) + v[i];result = a > b ? a : b;} s[i][j] = result;return result;}int main(){int i,j;for(i = 0;i < n;i ++)for(j = 0;j <= c;j ++)s[i][j] = -1;printf("%d\n",m(0,c));j = c;for(i = 0;i < n - 1;i ++)//先输出前n-1个物品中哪个放入了包中 {if(s[i][j] != s[i + 1][j]){printf("%d\t",i);j = j - w[i];}}if(j >= w[n - 1])//判断最后一个物品是否放入了包里 printf("%d\n",n - 1);return 0;}==========================================================================================// 动态规划#include<stdio.h>#define n 5#define c 10int main(){int i,j;int w[n] = {2,2,6,5,4};//表示每个物品的重量 int v[n] = {6,3,5,4,6};//每个物品的价值int s[n][c + 1];for(i = 0;i < n;i ++)for(j = 0;j <= c;j ++)s[i][j] = -1;for(j = 0;j <= c;j ++){if(j < w[n - 1])s[n - 1][j] = 0;else{s[n - 1][j] = v[n - 1];}}for(i = n - 2;i >= 0;i --){for(j = 0;j <= c;j ++){if(j < w[i])s[i][j] = s[i + 1][j];else{int a = s[i + 1][j - w[i]] + v[i];int b = s[i + 1][j];s[i][j] = a > b ? a : b;}} }for(i = 0;i < n;i ++){for(j = 0;j <= c;j ++)printf("%3d",s[i][j]);putchar('\n');}printf("%d\n",s[0][c]);j = c;for(i = 0;i < n - 1;i ++)//先输出前n-1个物品中哪个放入了包中 {if(s[i][j] != s[i + 1][j]){printf("%d\t",i);j = j - w[i];}}if(j >= w[n - 1])//判断最后一个物品是否放入了包里 printf("%d\n",n - 1);return 0;}
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