Blue Bridge Cup 01 backpack memory words Array

There are n items with a weight and value of Wi,vi respectively. Select items from these items that have a total weight of not more than W, and ask for the maximum value of the sum of all the values in the selection scheme

/**

* First items are recorded dynamically, and the total weight is less than J

* and keep the accepted records dynamically in the memory array

*/

#include <stdio.h>
#include <string.h>
int n,w;
int w[100],v[100];
Using a memory array
int dp[100][100];
int max (int n,int m) {
Return n>m?n:m;
}
Starting from Article I items, select the part with a total weight of less than J
int rec (int i,int j) {
If the current location is stored in the data, the data is returned directly
if (dp[i][j]>=0) return dp[i][j];
Record the current item weight
int res;
When the last item is selected, you can add a weight of 0
if (i==n) res=0;
If the current item weight is greater than the weight that can be added, the current item cannot be selected
else if (w[i]>j) Res=rec (I+1,J);
Else
Choose to select this item, or do not select the maximum weight of this item
Res=max (Rec (I+1,J), rec (i+1,j-w[i]) +v[i]);
Returns the maximum weight of the last item
Save data that has already been recorded
return dp[i][j]=res;
}
int main () {
while (scanf ("%d%d", &n,&w) ==2) {
Memset (Dp,-1,sizeof (DP));
for (int i=0;i<n;i++)
scanf ("%d%d", &w[i],&v[i]);
printf ("%d\n", rec (0,w));
}
return 0;
}

/************************************************ 2nd notation, recursive expression ************************************************** **/

#include <stdio.h>
#include <string.h>
int n,w;
int v[100],w[100];
DP for assistance Array
int dp[100][100];
int max (int n,int m) {
Return n>m?n:m;
}
VOID Rec () {
Choose from the last backpack
Use I to denote the backpack of the first I
for (int i=n-1;i>=0;i--)
J means the part with a total weight of less than J
for (int j=0;j<=w;j++) {
if (J<w[i]) dp[i][j]=dp[i+1][j];
else{
Dp[i][j]=max (Dp[i+1][j],dp[i+1][j-w[i]]+v[i]);
}
}
printf ("%d\n", Dp[0][w]);
}
int main () {
while (scanf ("%d%d", &n,&w) ==2) {
Memset (Dp,-1,sizeof (DP));
for (int i=0;i<n;i++)
scanf ("%d%d", &w[i],&v[i]);
Rec ();
}
return 0;
}

Blue Bridge Cup 01 backpack memory words Array