#include <bits/stdc++.h>
using namespace std;
template <class T>
inline bool mnto(T& a, T b) {return a > b ? a = b, 1 : 0;}
template <class T>
inline bool mxto(T& a, T b) {return a < b ? a = b, 1: 0;}
#define REP(i, s, e) for (int i = s; i < e; i++)
#define RREP(i, s, e) for (int i = s; i >= e; i--)
typedef long long ll;
typedef long double ld;
#define MP make_pair
#define FI first
#define SE second
typedef pair<int, int> ii;
typedef pair<ll, ll> pll;
#define MT make_tuple
typedef tuple<int, int, int> iii;
#define ALL(_a) _a.begin(), _a.end()
#define pb push_back
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<ii> vii;
#ifdef DEBUG
#define debug(args...) _debug(args)
void _debug(const char* format, ...) {
va_list args;
va_start(args, format);
vprintf(format, args);
va_end(args);
}
#else
#define debug(args...)
#endif
#define INF 1000000005
#define LINF 1000000000000000005
#define MOD 1000000007
#define MAXN 6005
int n, m;
char s[MAXN][MAXN];
int dp[MAXN][MAXN][3];
int ans;
bool rgw(int i, int j, bool isc) {
if (!isc) {
if (j + 2 >= m) return 0;
if (s[i][j] == 'R' && s[i][j + 1] == 'G' && s[i][j + 2] == 'W') {
return 1;
}
return 0;
} else {
if (i + 2 >= n) return 0;
if (s[i][j] == 'R' && s[i + 1][j] == 'G' && s[i + 2][j] == 'W') {
return 1;
}
return 0;
}
assert(0);
}
int main() {
scanf("%d%d", &n, &m);
REP (i, 0, n) {
scanf(" %s", s[i]);
}
int pi = 0, pj = 0;
dp[0][0][0] = rgw(0, 0, 0);
dp[0][0][2] = rgw(0, 0, 1);
REP (ij, 1, n + m - 1) {
REP (i, 0, s + 1) {
int j = ij - i;
if (i >= n || j >= m) continue;
if (rgw(i, j, 0)) {
dp[i][j][0] = dp[pi][pj][0] + 1;
if (i == 0) {
mxto(dp[i][j][0], max(dp[pi][pj][1], dp[pi][pj][2]) + 1);
}
}
if (rgw(i, j, 1)) {
dp[i][j][2] = max(dp[pi][pj][0],
max(dp[pi][pj][1], dp[pi][pj][2])) + 1;
}
REP (k, 0, 3) {
mxto(dp[i][j][max(k - 1, 0)], dp[pi][pj][k]);
}
debug("%d %d\n", i, j);
REP (k, 0, 3) {
debug(" %d: %d\n", k, dp[i][j][k]);
mxto(ans, dp[i][j][k]);
}
pi = i; pj = j;
}
}
printf("%d\n", ans);
return 0;
}
/*
3 4
RGWR
GRGG
RGWW
4 4
RGWR
GRRG
WGGW
WWWR
5 5
RGRGW
GRRGW
WGGWR
RWRGW
RGWGW
*/
Compilation message
dango_maker.cpp: In function 'int main()':
dango_maker.cpp:8:40: error: ISO C++ forbids comparison between pointer and integer [-fpermissive]
8 | #define REP(i, s, e) for (int i = s; i < e; i++)
......
73 | REP (i, 0, s + 1) {
| ~~~~~~~~~~~
dango_maker.cpp:73:3: note: in expansion of macro 'REP'
73 | REP (i, 0, s + 1) {
| ^~~
dango_maker.cpp:65:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
65 | scanf("%d%d", &n, &m);
| ~~~~~^~~~~~~~~~~~~~~~
dango_maker.cpp:67:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
67 | scanf(" %s", s[i]);
| ~~~~~^~~~~~~~~~~~~
