Go: package main

import (
	"bufio"
		"os"
	"strconv"
	"fmt"
)

var scanner = bufio.NewScanner(os.Stdin)

func main() {
	scanner.Split(bufio.ScanWords)
	for scanner.Scan() {
		table := [9][9]int{}
		check := [9][9]bool{}
		n, _ := strconv.Atoi(scanner.Text())
		for n > 0 {
			n--
			for i := 0; i < 9; i++ {
				for j := 0; j < 9; j++ {
					table[i][j] = nextInt()
				}
			}
			for i := 0; i < 9; i++ {
				for j := 0; j < 9; j++ {
					ok := true
					for k := 0; k < 9; k++ {
						if table[i][j] == table[i][k] && j != k {
							ok = false
						}
					}
					for k := 0; k < 9; k++ {
						if table[i][j] == table[k][j] && i != k {
							ok = false
						}
					}
					seci := i/3
					secj := j/3
					for k := 0; k < 3; k++ {
						for l := 0; l > 3; l++ {
							if table[seci*3+k][secj*3+l]==table[i][j]&&seci*3+k!=i&&secj*3+l!=j {
								ok = false
							}
						}
					}
					if !ok {
						check[i][j] = true
					}
				}
			}
			for i := 0; i < 9; i++ {
				for j := 0; j < 9; j++ {
					if check[i][j] {
						fmt.Print("*")
					} else {
						fmt.Print(" ")
					}
					fmt.Print(table[i][j])
				}
				fmt.Println()
			}
			if n != 0 {
				fmt.Println()
			}
		}
	}
}

func nextInt() int {
	scanner.Scan()
	i, e := strconv.Atoi(scanner.Text())
	if e != nil {
		panic(e)
	}
	return i
}

C++: #include <iostream>
#include <cstdio>

using namespace std;

int puzzle[10][10];
int col[10][10], row[10][10]; // 列，行
bool check[10][10];  // 間違っている場合はfalse
int n;

/*
  rect[0] rect[1] rect[2]
  rect[3] rect[4] rect[5]
  rect[6] rect[7] rect[8]
*/
int rect[10][10];

void solve()
{
    // 行・列のチェック
    for (int i = 0; i < 9; i++) {
        for (int j = 0; j < 9; j++) {
            // 列のチェック
            if (col[j][puzzle[i][j] - 1] != -1) {
                int bf = col[j][puzzle[i][j] - 1];
                check[bf][j] = check[i][j] = false;
                col[j][puzzle[i][j] - 1] = i;
            }
            else
                col[j][puzzle[i][j] - 1] = i;

            // 行のチェック
            if (row[i][puzzle[i][j] - 1] != -1) {
                int bf = row[i][puzzle[i][j] - 1];
                check[i][bf] = check[i][j] = false;
                row[i][puzzle[i][j] - 1] = j;
            }
            else
                row[i][puzzle[i][j] - 1] = j;
        }
    }

    // 3x3の領域のチェック
    for (int i = 0; i < 9; i++) {
        for (int j = 0; j < 3; j++) {
            for (int k = 0; k < 3; k++) {
                int x = (i % 3) * 3 + k;
                int y = (i / 3) * 3 + j;

                if (rect[i][puzzle[y][x] - 1] != -1) {
                    int nx = (i % 3) * 3 + (rect[i][puzzle[y][x] - 1] % 3);
                    int ny = (i / 3) * 3 + (rect[i][puzzle[y][x] - 1] / 3);

                    check[ny][nx] = check[y][x] = false;
                    rect[i][puzzle[y][x] - 1] = j * 3 + k;
                }
                else
                    rect[i][puzzle[y][x] - 1] = j * 3 + k;                    
            }
        }
    }

    for (int i = 0; i < 9; i++)
        for (int j = 0; j < 9; j++) {
            if (check[i][j]) 
                printf(" %d", puzzle[i][j]);
            else
                printf("*%d", puzzle[i][j]);
            
            if (j + 1 == 9)
                putchar('\n');
        }
}

int main()
{
    cin >> n;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < 9; j++)
            for (int k = 0; k < 9; k++) {
                cin >> puzzle[j][k];
                col[j][k] = row[j][k] = rect[j][k] = -1;
                check[j][k] = true;
            }

        if (i != 0)
            putchar('\n');
        solve();
    }
        

    return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<climits>
#include<cmath>
#include<cstdio>
#include<cstdlib>
#include<ctime>
#include<string>
#include<cstring>
#include<vector>
#include<stack>
#include<queue>
#include<set>
#include<map>
#include<bitset>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> i_i;

#define PI 3.141592653589793238462643383279
#define mod 1000000007LL
#define rep(i, n) for(i = 0;i < n;++i)
#define rep1(i, n) for(i = 1;i < n;++i)
#define per(i, n) for(i = n - 1;i > -1;--i)
#define int(x) int x; scanf("%d",&x)
#define int2(x, y) int x, y; scanf("%d%d",&x, &y)
#define int3(x, y, z) int x, y, z; scanf("%d%d%d",&x, &y, &z)
#define int4(v, x, y, z) int v, x, y, z; scanf("%d%d%d%d", &v, &x, &y, &z)
#define int5(v, w, x, y, z) int v, w, x, y, z; scanf("%d%d%d%d%d", &v, &w, &x, &y, &z)
#define ll2(x, y) ll x, y; cin >> x >> y;
#define scn(n, a) rep(i, n)cin >> a[i]
#define sc2n(n, a, b) rep(i, n)cin >> a[i] >> b[i]
#define pri(x) cout << (x) << "\n"
#define pri2(x, y) cout << (x) << " " << (y) << "\n"
#define pri3(x, y, z) cout << (x) << " " << (y) << " " << (z) << "\n"
#define pb push_back
#define mp make_pair
#define all(a) (a).begin(),(a).end()
#define endl "\n"
#define kabe puts("---------------------------")
#define kara puts("")
#define debug(x) cout << " --- " << (x) << "\n"
#define debug2(x, y) cout << " --- " << (x) << " " << (y) << "\n"
#define debug3(x, y, z) cout << " --- " << (x) << " " << (y) << " " << (z) << "\n"
#define X first
#define Y second
#define eps 0.0001
#define prid(x) printf("%.15lf\n", x)

int f[9][9];
int dh[9] = {0, 0, 0, 1, 1, 1, 2, 2, 2};
int dw[9] = {0, 1, 2, 0, 1, 2, 0, 1, 2};

signed main(void){
  int i, j, k, l, m;
  int(n);
  for(int testcase = 0;testcase < n;testcase++){
    if(testcase != 0)puts("");
    rep(i, 9)rep(j, 9)scanf("%d", &f[i][j]);
    rep(i, 9){
      rep(j, 9){
        bool is = true;
        rep(k, 9){
          if(i != k)if(f[i][j] == f[k][j])is = false;
          if(j != k)if(f[i][j] == f[i][k])is = false;
          if(i % 3 != dh[k] && j % 3 != dw[k])
          if(f[i][j] == f[i / 3 * 3 + dh[k]][j / 3 * 3 + dw[k]])is = false;
        }
        if(is)printf(" %d", f[i][j]);
        else printf("*%d", f[i][j]);
      }
      puts("");
    }


//*/

//*/ break;
  }
  return 0;
}