请各位大佬有时间可以瞅一眼，剪枝策略大致没啥问题，使用一个一个空填的思路（而不是一行一行地填），95分。有一个点RE，本机能过。

代码：

#include<bits/stdc++.h>
using namespace std;
int mp[15][15],row[15][15],col[15][15],ar[15][15],nor[15],noc[15],noa[15],tot,ans;
struct blank {
	int x,y,r,vx,vy,vr;
	bool operator < (const blank &k) const {
		if(vx != k.vx)
			return vx < k.vx;
		if(vy != k.vy)
			return vy < k.vy;
		if(vr != k.vr)
			return vr < k.vr;
	}
} bl[90];
const int val[90] = {
	0,6,6,6,6,6,6,6,6,6,
	6,7,7,7,7,7,7,7,6,
	6,7,8,8,8,8,8,7,6,
	6,7,8,9,9,9,8,7,6,
	6,7,8,9,10,9,8,7,6,
	6,7,8,9,9,9,8,7,6,
	6,7,8,8,8,8,8,7,6,
	6,7,7,7,7,7,7,7,6,
	6,6,6,6,6,6,6,6,6
};
int cnt = 0;
void dfs(int m) {
	cnt++;
	if(m == tot + 1) {
		int tmp = 0;
		for(int i = 1; i <= 9; i++) {
			for(int j = 1; j <= 9; j++) {
				int pos = (i - 1) * 9 + j;
				tmp += mp[i][j] * val[pos];
			}
		}
		ans = max(ans,tmp);
		return;
	}
	int mx = bl[m].x,my = bl[m].y,mr = bl[m].r;
	for(int i = 1; i <= 9; i++) {
		if(row[mx][i] || col[my][i] || ar[mr][i]) continue;
		mp[mx][my] = i;
		row[mx][i] = 1;
		col[my][i] = 1;
		ar[mr][i] = 1;
		dfs(m + 1);
		row[mx][i] = 0;
		col[my][i] = 0;
		ar[mr][i] = 0;
	}
	return;
}
int main() {
	for(int i = 1; i <= 9; i++)
		for(int j = 1; j <= 9; j++) {
			scanf("%d",&mp[i][j]);
			if(!mp[i][j]) {
				nor[i]++;
				noc[j]++;
				bl[++tot].x = i;
				bl[tot].y = j;
				if(i <= 3) {
					if(j <= 3)
						bl[tot].r = 1;
					else if(j <= 6)
						bl[tot].r = 2;
					else
						bl[tot].r = 3;
				} else if(i <= 6) {
					if(j <= 3)
						bl[tot].r = 4;
					else if(j <= 6)
						bl[tot].r = 5;
					else
						bl[tot].r = 6;
				} else {
					if(j <= 3)
						bl[tot].r = 7;
					else if(j <= 6)
						bl[tot].r = 8;
					else
						bl[tot].r = 9;
				}
				noa[bl[tot].r]++;
			} else {
				int tmp;
				if(i <= 3) {
					if(j <= 3) tmp = 1;
					else if(j <= 6) tmp = 2;
					else tmp = 3;
				} else if(i <= 6) {
					if(j <= 3) tmp = 4;
					else if(j <= 6) tmp = 5;
					else tmp = 6;
				} else {
					if(j <= 3) tmp = 7;
					else if(j <= 6) tmp = 8;
					else tmp = 9;
				}
				row[i][mp[i][j]] = 1;
				col[j][mp[i][j]] = 1;
				ar[tmp][mp[i][j]] = 1;
			}
		}
	for(int i = 1; i <= tot; i++) {
		bl[i].vx = nor[bl[i].x];
		bl[i].vy = noc[bl[i].y];
		bl[i].vr = nor[bl[i].r];
	}
	sort(bl + 1,bl + tot + 1);
	dfs(1);
	if(ans == 0) {
		printf("-1");
		return 0;
	}
	printf("%d\n",ans);
	return 0;
}