01背包-近似算法

void dp2(int *w, int *v, int n, int c){cout<<"dp2:"<<endl;
int vs = 0;
for(int i=0;i<n;i++)
vs += v[i];
int **m;
m = new int*[n+1];
for (int i = 0; i<n + 1; i++) {
m[i] = new int[vs+1];
for (int j = 0; j<vs + 1; j++)
m[i][j]=-1;//2147483647
}
for(int i=0;i<n+1;i++) m[i][0] = 0;
m[1][v[0]] = w[0];
for(int i=2;i<=n;i++){
for(int j=1;j<=vs;j++){
if(j<v[i-1])
m[i][j] = m[i-1][j];
else{
int a = m[i-1][j];
int b = m[i-1][j-v[i-1]];
if(b==-1){
m[i][j] = a;
}
else{
b += w[i-1];
if(a==-1||b<a) m[i][j] = b;
else m[i][j] = a;
}
}
}
}
//	for (int i = 0; i <= n; i++) {
//		for (int j = 0; j <= vs; j++) cout << m[i][j] << "\t";
//		cout << endl;
//	}

int *x;
x = new int[n+1];
int maxV=0;
for(int i=vs;i>0;i--){
if(m
[i]<=c&&m
[i]!=-1){
maxV = i;
break;
}
}
for(int i=n;i>0;i--){
if(m[i][maxV]==m[i-1][maxV]) x[i] = 0;
else {
x[i] = 1;
maxV -= v[i-1];
}
}
//	for (int i = 1; i <= n; i++) cout << x[i] << "\t";
cout << endl;
}
void adp(int *w, int *v, int n, int c,int e){cout<<"adp:"<<endl;
int k = n/e;
int vmax = 0;
for(int i=0;i<n;i++)
if(vmax<v[i])
vmax=v[i];
for(int i=0;i<n;i++)
v[i] = v[i]*k/vmax;
dp2(w, v, n, c);
}