Sum(N) =1^1+2^2+3^3+...+N^N
使用Java,我将如何BigInteger
找到最小整数N,使得Sum(N) 的值大于10 ^ 20?我真的卡住了,请给我一些建议
这是我到目前为止所拥有的:
import java.math.BigInteger;
public class PROJECTV1 {
public static void main(String [] args) {
BigInteger bResult= bigFunctionExample_2();
System.out.println(" => result_got:"+ bResult);
System.out.println(); //newline
}// end_main
public static BigInteger bigFunctionExample_2() {
BigInteger bSum = BigInteger.ZERO;
BigInteger bTmp;
String sSum;
// BigInteger bResult =0;
for (int i=1; ; i++) {
bTmp = BigInteger.valueOf(i);
bTmp = bTmp.pow(i); // i^i
bSum = bSum.add(bTmp); // sum = i^i+ (i-1)^(i-1)+ ....
sSum = bSum.toString();
if ( sSum.length() >21) {
System.out.println("i="+i +" bSum ="+bSum);
break;
}//
}//end_for
return bSum; // result
} // end_bigFunctionExample_2
}