Border (Çözgüdiň düşündirişi)

Store the rectangular area in a character array. Consider the element $s[i][j]$. If it differs from s[i + 1][j], then there is a border of length $1$ between them (that is, there is a border below $s[i][j]$).

Similarly, if $s[i][j]$ differs from s[i][j + 1], then there is also a border of length $1$ between them (that is, there is a border to the right of $s[i][j]$).

It remains to iterate over all positions $(i,j)$ and, for each of them, count the number of bottom and right borders.

Example

The border between the states is shown in red. Its length is $13$.

Algorithm implementation

The territories of the states are stored in the array $s$.

#define MAX 110
char s[MAX][MAX];

Read the input data.

scanf("%d %d\n", &w, &h);
for (i = 0; i < h; i++)
  gets(s[i]);

Compute the total length of the vertical borders.

for (i = 0; i < h; i++)
for (j = 0; j < w - 1; j++)
  if (s[i][j] != s[i][j + 1]) res++;

Compute the total length of the horizontal borders.

for (i = 0; i < h - 1; i++)
for (j = 0; j < w; j++)
  if (s[i][j] != s[i + 1][j]) res++;

Print the answer.

printf("%d\n", res);

Algorithm implementation – string

The territories of the states are stored in the array $s$.

vector<string> s;

Read the input data.

cin >> w >> h;
s.resize(h);
for (i = 0; i < h; i++)
  cin >> s[i];

Compute the total length of the vertical borders.

for(i = 0; i < h; i++)
for(j = 0; j < w - 1; j++)
  if (s[i][j] != s[i][j+1]) res++;

Compute the total length of the horizontal borders.

for(i = 0; i < h - 1; i++)
for(j = 0; j < w; j++)
  if (s[i][j] != s[i+1][j]) res++;

Print the answer.

cout << res << endl;