使用BigInteger实现
做法十分暴力,一定要超时的,不知道用例有没有作时间限制。
贴出来给大家图一乐⑧
import java.math.BigInteger; import java.util.Scanner; public class Solution2 { public static void main(String[] args) { Scanner sc = new Scanner(System.in); int n =sc.nextInt(); int m =sc.nextInt(); int k =sc.nextInt(); BigInteger sum=new BigInteger("0"); for (int i = 3; i <= n; i++) { for (int j = 2; j <= m; j++) { if(i+j==k) { BigInteger temp1 = get(new BigInteger(n+"")).divide(get(new BigInteger(i+"")).multiply(get(new BigInteger((n-i)+"")))); BigInteger temp2 = get(new BigInteger(m+"")).divide(get(new BigInteger(j+"")).multiply(get(new BigInteger((m-j)+"")))); sum= sum.add((temp1.multiply(temp2))); if (sum.intValue() > 1000000007) { sum = sum.remainder(new BigInteger("1000000007")); } } } } System.out.println(sum.remainder(new BigInteger("1000000007"))); } private static BigInteger get(BigInteger m) { BigInteger temp = new BigInteger("1"); if (m.intValue()==0) { return temp; } for (int i = 1; i <= m.intValue(); i++) { temp = temp.multiply(new BigInteger(i+"")); } return temp; } }
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