Finally finished the second half of day 3.

2021/3/main2.py

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+bits = []
+
+gamma = 0
+epsilon = 0
+
+gamma_str = ''
+epsilon_str = ''
+
+lines = []
+oxy = []
+co2 = []
+
+def NarrowDown(oxy, co2, index):
+    # # DEBUG(dev):
+    # print len(oxy), ", ", len(co2)
+    # print ""
+
+    if(len(oxy) > 1): # if we already found it, just move along
+        # Look at `index` in each remaining value; count how many have a ZERO vs. a ONE:
+        num_ones = 0
+        num_zeros = 0
+        new_oxy = []
+        for i,o in enumerate(oxy):
+            if(o[index] == '1'):
+                num_ones = num_ones + 1
+            else:
+                num_zeros = num_zeros + 1
+
+        # Oxy needs the majority, keeping the ONEs if there's a tie:
+        if(num_ones < num_zeros):
+            for o in oxy:
+                if(o[index] == '0'):
+                    new_oxy.append(o)
+        else:
+            for o in oxy:
+                if(o[index] == '1'):
+                    new_oxy.append(o)
+        oxy = list(new_oxy)
+
+    if(len(co2) > 1): # if we already found it, just move along
+        # Look at `index` in each remaining value; count how many have a ZERO vs. a ONE:
+        num_ones = 0
+        num_zeros = 0
+        new_co2 = []
+        for i,o in enumerate(co2):
+            if(o[index] == '1'):
+                num_ones = num_ones + 1
+            else:
+                num_zeros = num_zeros + 1
+
+        # Co2 needs the minority, keeping the ZEROs if there's a tie:
+        if(num_ones < num_zeros):
+            for c in co2:
+                if(c[index] == '1'):
+                    new_co2.append(c)
+        else:
+            for c in co2:
+                if(c[index] == '0'):
+                    new_co2.append(c)
+        co2 = list(new_co2)
+
+    # if we're down to one number in BOTH LISTS, we're done
+    if(len(oxy) == 1 and len(co2) == 1):
+        return oxy[0],co2[0]
+
+    # otherwise, pass both remaining lists on, move over one index, and continue narrowing down:
+    return NarrowDown(oxy, co2, (index + 1))
+
+
+
+#### MAIN EXECUTION ####
+with open('data', 'r') as fp:
+    for line in fp:
+        lines.append(line.strip())
+
+# NOTE(dev): We assume all lines are the same length
+for i in range(0, len(lines[0])):
+    bits.append(0)
+
+# # DEBUG(dev):
+# test = fp.readline()
+# for i in range(0, len(test)):
+#     print test[i]
+
+for line in lines:
+    for i in range(0, len(line.strip())):
+        if(line[i] == '1'):
+            bits[i] = bits[i] + 1
+        else:
+            bits[i] = bits[i] - 1
+
+for i in range(0, len(bits)):
+    ch = '1'
+    if(bits[i] < 0):
+        ch = '0'
+    gamma_str = gamma_str + ch
+
+# # DEBUG(dev):
+# for i in range(1, len(gamma_str)+1):
+#     print gamma_str[-i]
+
+# NOTE(dev): Have to do (i+1) because we're going backwards, which starts at -1
+for i in range(0, len(gamma_str)):
+    if(gamma_str[-(i+1)] == '1'):
+    	gamma = gamma + pow(2,i)
+    else:
+    	epsilon = epsilon + pow(2,i)
+
+# print "   bits: ", bits
+print "  gamma: ", gamma
+print "epsilon: ", epsilon
+print "  POWER: ", gamma * epsilon
+
+oxy = list(lines)
+co2 = list(lines)
+
+oxy_str,co2_str = NarrowDown(oxy, co2, 0)
+oxy_value = 0
+co2_value = 0
+
+# convert binary string representation to decimal
+for i in range(0, len(oxy_str)):
+    if(oxy_str[-(i+1)] == '1'):
+    	oxy_value = oxy_value + pow(2,i)
+
+# convert binary string representation to decimal
+for i in range(0, len(co2_str)):
+    if(co2_str[-(i+1)] == '1'):
+    	co2_value = co2_value + pow(2,i)
+
+print "oxy: ", oxy_value
+print "co2: ", co2_value
+print "   : ", oxy_value * co2_value