importjava.util.*;classSolution{privatestaticfinaldoubleEPS1e-6;publicbooleanjudgePoint24(int[]cards){ListDoublenumsnewArrayList();for(intcard:cards){nums.add((double)card);}returndfs(nums);}privatebooleandfs(ListDoublenums){if(nums.size()1){returnMath.abs(nums.get(0)-24.0)EPS;}intnnums.size();for(inti0;in;i){for(intj0;jn;j){if(ij)continue;doubleanums.get(i);doublebnums.get(j);ListDoublenextnewArrayList();for(intk0;kn;k){if(k!ik!j){next.add(nums.get(k));}}// Try a b, a - b, b - a, a * bdouble[]results{ab,a-b,b-a,a*b};for(doubleval:results){next.add(val);if(dfs(next))returntrue;next.remove(next.size()-1);}// Try a / bif(Math.abs(b)EPS){next.add(a/b);if(dfs(next))returntrue;next.remove(next.size()-1);}// Try b / aif(Math.abs(a)EPS){next.add(b/a);if(dfs(next))returntrue;next.remove(next.size()-1);}}}returnfalse;}}