【HDOJ】4504 威威猫系列故事——篮球梦

#include <cstdio>
#include <cstdlib>
#include <cstring>

#define MAXN 25
int dp[MAXN][MAXN*3];

void init() {
int i, j, k;

memset(dp, 0, sizeof(dp));
dp[0][0] = dp[1][1] = dp[1][2] = dp[1][3] = 1;
for (i=2; i<MAXN; ++i) {
for (j=0; j<MAXN*3; ++j) {
dp[i][j] += dp[i-1][j-1];
if (j >= 2)
dp[i][j] += dp[i-1][j-2];
if (j >= 3)
dp[i][j] += dp[i-1][j-3];
}
}
}

int main() {
int a, b, t;
int i, j, k, tmp;
int mmin, mmax;
__int64 ans;

#ifndef ONLINE_JUDGE
freopen("data.in", "r", stdin);
#endif

init();

while (scanf("%d %d %d", &a, &b, &t) != EOF) {
i = t / 15;
j = (i+1) / 2;
if (b < a) {
tmp = a - b;
mmin = j;
mmax = j * 3;
} else {
tmp = b - a;
mmin = tmp + i - j + 1;
mmax = j * 3;
}
ans = 0;
for (k=mmin; k<=mmax; ++k)
ans += dp[j][k];
printf("%I64d\n", ans);
}

return 0;
}