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[n][i]<=c&&m[n][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);
}