最大连续邮资问题的JAVA实现

public class StampCost {
int m;
int n;
int stamps[];
int maxNum = 0;
int[] tempset;
int current;
int rightPos;
int base;
public StampCost(int m,int n,int[] stamps){
this.m = m;
this.n = n;
this.stamps = stamps;
check();
printResult();
}

public void check(){
tempset = new int[stamps[(stamps.length-1)]*4+1];
maxNum = m;//因为第一个确定是1，所以初始化最大的面值就是 1*m
for (int i=1;i<5;i++){
int min = Math.max(stamps[i],maxNum)+1;;
int max = stamps[i]*m;
if (min < stamps[i]+1){
return;
}
maxNum = min-1;
tempset[maxNum]=1;
if (!checkSpan(min,max,i)){
return;
}
}
}

public boolean checkSpan(int min,int max,int rightPos){
base = min;
current=stamps[rightPos];
this.rightPos = rightPos;
backtrace(0);
if (tempset[min] == 0){
return false;
}
for (int i=min;i<max;i++){
if (tempset[i] == 0){
return true;
}
else{
maxNum++;
}
}
return true;
}

public void backtrace(int i){
if (i >= (m-1)){
return;
}
else{
for (int j=0;j<rightPos+1;j++){
current += stamps[j];
if (current >= base){
tempset[current] = 1;
}
backtrace(i+1);
current -= stamps[j];
}
}
}

public void printResult(){
System.out.println(maxNum);
}

public static void main(String args[]){
int m=4;
int n=5;
int[] stamps={1,3,11,15,32};
new StampCost(m,n,stamps);
}
}