Ruudukko

const { readSync,readFileSync } = require('fs');
const { Buffer } = require('buffer');


function readline() {
  let buf = Buffer.alloc(1000, 10);
  for(i=0; i<1000; i++) {
    if(!readSync(0, buf, i, 1) || buf[i]===10) {
      return buf.toString("utf8").split("\n")[0];
    }
  }
}

const mod = 1e9+7;
const n = Number(readline());

const tablestr = readFileSync(0,{encoding:"utf8"});
let table = [];

let itemstr = "";
for(let i=0; i<tablestr.length; i++) {
  switch (tablestr[i]) {
    case " ":
    case "\n":
      itemstr&&table.push(parseInt(itemstr));
      itemstr="";
      break;
    default:
      itemstr+=tablestr[i];
  }
}

let nummap = Array(n**2+10).fill();
//const nummap = Array(n**2+10).fill().map(()=>[]);

//console.log(table.length);

table.forEach((e,i)=>nummap[e]?nummap[e].push(i):nummap[e]=[i]);
//table.forEach((e,i)=>nummap[e].push(i));

let paths = Array(n**2).fill(0);
let xpaths = Array(n).fill(0);
let ypaths = Array(n).fill(0);
let newxpaths = [];
let newypaths = [];

nummap.forEach((a,i)=>{
//  if(!(i%1000)) console.log(i);
  if(a) {
    newxpaths = [];
    newypaths = [];
    a.forEach(e=>{
      let x=e%n;
      let y=e/n|0;
      let b=(1+xpaths[x]+ypaths[y])%mod;
//      console.log(i,b);
      newxpaths.push([x,b]);
      newypaths.push([y,b]);
      paths[e]=b;
    });
    newxpaths.forEach(e=>xpaths[e[0]]+=e[1]);
    newypaths.forEach(e=>ypaths[e[0]]+=e[1]);
//    console.log(xpaths, ypaths);

  }
});

console.log(paths.reduce((v,e)=>(v+e)%mod,0).toString());

Test 1

Group: 1, 2, 3

Verdict: ACCEPTED

Test 2

Group: 1, 2, 3

Verdict: ACCEPTED

Test 3

Group: 1, 2, 3

Verdict: ACCEPTED

Test 4

Group: 2, 3

Verdict: ACCEPTED

Test 5

Group: 2, 3

Verdict: ACCEPTED

Test 6

Group: 2, 3

Verdict: ACCEPTED

Test 7

Group: 3

Verdict: ACCEPTED

Test 8

Group: 3

Verdict: ACCEPTED

Test 9

Group: 3

Verdict: TIME LIMIT EXCEEDED