Question: Give you three sequences and let you take pairs of numbers. These two numbers are in different sequences. Each number can only be taken once, letting you find the maximum sum of the products of all pairs of two numbers.
Idea: First sort the three arrays from small to large, then use dfs in three ways, and perform recursion on each recursive layer. dp[i][j][k] represents the sum of the largest products that can be obtained by using i R, j G, and k Bs.
var readline=require('readline');
var rl=readline.createInterface({
input:process.stdin,
output:process.stdout
});
var arr=[],sol;
function Solve(){
this.val=0;
this.dp=new Array(205);
for(var i=0;i<205;i++){
this.dp[i]=new Array(205);
for(var j=0;j<205;j++) this.dp[i][j]=new Array(205).fill(0);
}
}
Solve.prototype.dfs=function(i,j,k){
if(i<0||j<0||k<0) return 0;
if(this.dp[i][j][k]) return this.dp[i][j][k];
var x=0,y=0,z=0;
x=this.dfs(i-1,j-1,k)+(i>0&&j>0?(this.a[0][i-1]*this.a[1][j-1]):0);
y=this.dfs(i-1,j,k-1)+(i>0&&k>0?(this.a[0][i-1]*this.a[2][k-1]):0);
z=this.dfs(i,j-1,k-1)+(j>0&&k>0?(this.a[1][j-1]*this.a[2][k-1]):0);
return this.val=this.dp[i][j][k]=Math.max(x,Math.max(y,z));
}
Solve.prototype.init=function(){
this.a=new Array(3);
}
rl.on('line',function(inp){
arr.push(inp);
var len=arr.length;
if(len===1){
sol=new Solve();
sol.rgb=arr[0].split(' ');
sol.init();
for(var i=0;i<sol.rgb.length;i++) sol.rgb[i]=parseInt(sol.rgb[i]);
}else{
var b=arr[len-1].split(' ');
for(var i=0;i<sol.rgb[len-2];i++) b[i]=parseInt(b[i]);
sol.a[len-2]=b;
sol.a[len-2].sort(function(x,y){
if(x<y) return -1;
else if(x===y) return 0;
else return 1;
});
}
if(len===4){
sol.dfs(sol.rgb[0],sol.rgb[1],sol.rgb[2]);
console.log(sol.val);
process.exit(0);
}
});