USACO Home on the Range

参考USACO，使用的动态规划 http://www.nocow.cn/index.php/USACO/range

代码

/*
ID: wangxin12
PROG: range
LANG: C++
*/

#include <iostream>
#include <fstream>
#define MAX 253

using namespace std;

ofstream fo("range.out");
ifstream fi("range.in");

int N; // 1 < N <= 250
int map[MAX][MAX];
int num[MAX];

void readData() {
fi>>N;
int i, j;
for(i = 1; i <= N; i++) {
for(j = 1; j <= N; j++) {
char c;
fi>>c;
if(c == '0')
map[i][j] = 0;
else if(c == '1')
map[i][j] = 1;
}
}
}

int getMin(int a, int b, int c) {
int tmp;
if(a < b) tmp = a;
else tmp = b;

if(tmp < c) return tmp;
else return c;
}

void calculte() {
int i, j, k;
for(i = N - 1; i >= 1; i--)
for(j = N - 1; j >= 1; j--) {
if(map[i][j])
map[i][j] = getMin(map[i + 1][j], map[i][j + 1], map[i + 1][j + 1]) + 1;
}

for(i = 1; i <= N; i++)
for(j = 1; j <= N; j++)
for(k = 2; k <= map[i][j]; k++)
num[k]++;
}

void output() {
for(int i = 2; i <= N; i++) {
if(num[i])
fo << i << " " << num[i] << endl;
}
}

int main() {
readData();

calculte();

output();

//cout << "Hello" << endl;
fo.close();
fi.close();
return 0;
}

我的第一次代码在test 7 （所有数据全是1）超时，倒是能算出正确答案了。

/*
ID: wangxin12
PROG: range
LANG: C++
*/

#include <iostream>
#include <fstream>
#define MAX 253

using namespace std;

ofstream fo("out.txt");
ifstream fi("in.txt");

int N;  // 1 < N <= 250
int map[MAX][MAX];
int num[MAX];

void readData() {
fi>>N;
int i, j;
for(i = 1; i <= N; i++) {
for(j = 1; j <= N; j++) {
char c;
fi>>c;
if(c == '0')
map[i][j] = 0;
else if(c == '1')
map[i][j] = 1;
}
}
}

bool extend(int row, int col) {
int len = map[row][col];
int i, j, x = 0, y = 0;
for(i = row + len, j = col; j < col + len + 1; j++) {
if(map[i][j]) x++;
}
if(x != len + 1) return false;

for(i = row, j = col + len; i < row + len + 1; i++) {
if(map[i][j]) y++;
}

if(y != len + 1)
return false;

return true;
}

void calculate(int index) {
if(index >= MAX) return;

for(int i = 1; i < MAX; i++)
for(int j = 1; j < MAX; j++) {
if(map[i][j] == index) {
if(extend(i,j)) {
map[i][j]++;
num[index + 1]++;
}
}
}
}

void output() {
for(int i = 2; i <= N; i++) {
if(num[i])
fo << i << " " << num[i] << endl;
}
}

int main() {
readData();

for(int t = 1; t <= N; t++)
calculate(t);

output();

//cout << "Hello" << endl;
fo.close();
fi.close();
return 0;
}